* Re: [PATCH 1/4] pwm_backlight: Fix PWM levels support in non DT case
From: Peter Ujfalusi @ 2013-01-29 8:17 UTC (permalink / raw)
To: Thierry Reding
Cc: Richard Purdie, Grant Likely, Rob Landley,
Florian Tobias Schandinat, Andrew Morton, devicetree-discuss,
linux-doc, linux-kernel, linux-fbdev
In-Reply-To: <20130128210123.GA24673@avionic-0098.mockup.avionic-design.de>
On 01/28/2013 10:01 PM, Thierry Reding wrote:
> On Tue, Jan 22, 2013 at 02:39:53PM +0100, Peter Ujfalusi wrote:
>> It is expected that board files would have:
>> static unsigned int bl_levels[] = { 0, 50, 100, 150, 200, 250, };
>>
>> static struct platform_pwm_backlight_data bl_data = {
>> .levels = bl_levels,
>> .max_brightness = ARRAY_SIZE(bl_levels),
>> .dft_brightness = 4,
>> .pwm_period_ns = 7812500,
>> };
>>
>> In this case the max_brightness would be out of range in the levels array.
>> Decrement the received max_brightness in every case (DT or non DT) when the
>> levels has been provided.
>
> What's wrong with specifying .max_brightness = ARRAY_SIZE(bl_levels) - 1
> instead?
There is nothing wrong with that either but IMHO it is more natural for board
files to use just ARRAY_SIZE(bl_levels). In this way the handling of
data->max_brightness among non DT and DT booted kernel is more uniform in the
driver itself.
Right now all board files are using only the .max_brightness to specify the
maximum value, I could not find any users of .levels in the kernel.
--
Péter
^ permalink raw reply
* Re: [PATCH 4/4] pwm_backlight: Add support for the whole range of the PWM in DT mode
From: Thierry Reding @ 2013-01-29 10:00 UTC (permalink / raw)
To: Peter Ujfalusi
Cc: Richard Purdie, Grant Likely, Rob Landley,
Florian Tobias Schandinat, Andrew Morton, devicetree-discuss,
linux-doc, linux-kernel, linux-fbdev
In-Reply-To: <1358861996-27194-5-git-send-email-peter.ujfalusi@ti.com>
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On Tue, Jan 22, 2013 at 02:39:56PM +0100, Peter Ujfalusi wrote:
> When booting with DT make it possible to use the whole range of the PWM when
> controlling the backlight in a same way it is possible when the kernel is
> booted in non DT mode.
> A new property "max-brightness-level" can be used to specify the maximum
> value the PWM can handle (time slots).
> DTS files can use either the "brightness-levels" or the "max-brightness-level"
> to configure the PWM.
> In case both of these properties exist the driver will prefer the
> "brightness-levels" over the "max-brightness-level".
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
I don't think this is a good idea. The brightness-levels property was
specifically introduced in order to have a more reasonable interface to
specify brightness levels.
As such, all uses of the non-DT max_brightness to be deprecated. It is
only kept for backwards compatibility with non-DT boards.
Thierry
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^ permalink raw reply
* Re: [PATCH 1/4] pwm_backlight: Fix PWM levels support in non DT case
From: Thierry Reding @ 2013-01-29 10:17 UTC (permalink / raw)
To: Peter Ujfalusi
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA, Florian Tobias Schandinat,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, Richard Purdie,
Andrew Morton
In-Reply-To: <51078580.2000808-l0cyMroinI0@public.gmane.org>
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On Tue, Jan 29, 2013 at 09:17:04AM +0100, Peter Ujfalusi wrote:
> On 01/28/2013 10:01 PM, Thierry Reding wrote:
> > On Tue, Jan 22, 2013 at 02:39:53PM +0100, Peter Ujfalusi wrote:
> >> It is expected that board files would have:
> >> static unsigned int bl_levels[] = { 0, 50, 100, 150, 200, 250, };
> >>
> >> static struct platform_pwm_backlight_data bl_data = {
> >> .levels = bl_levels,
> >> .max_brightness = ARRAY_SIZE(bl_levels),
> >> .dft_brightness = 4,
> >> .pwm_period_ns = 7812500,
> >> };
> >>
> >> In this case the max_brightness would be out of range in the levels array.
> >> Decrement the received max_brightness in every case (DT or non DT) when the
> >> levels has been provided.
> >
> > What's wrong with specifying .max_brightness = ARRAY_SIZE(bl_levels) - 1
> > instead?
>
> There is nothing wrong with that either but IMHO it is more natural for board
> files to use just ARRAY_SIZE(bl_levels). In this way the handling of
> data->max_brightness among non DT and DT booted kernel is more uniform in the
> driver itself.
The .max_brightness field is defined to be the maximum value that you
can set the brightness to. If you use .levels and set .max_brightness to
ARRAY_SIZE() then that's no longer true because the maximum value for
the brightness will actually be ARRAY_SIZE() - 1.
The reason why in the DT case we decrement .max_brightness is that it is
used as a temporary variable to keep the number of levels, which
corresponds to ARRAY_SIZE() in your example, and adjust it later on to
match the definition. That's an implementation detail.
Platform data content should be encoded properly without knowledge of
the internal implementation.
> Right now all board files are using only the .max_brightness to specify the
> maximum value, I could not find any users of .levels in the kernel.
Yes. But this is the legacy mode which should be considered deprecated.
The reason why the concept of brightness-levels was introduced back when
the DT bindings were created was that pretty much no hardware in
existence actually works that way. This was a topic of discussion at the
time when I first proposed these changes, see for example:
http://www.mail-archive.com/devicetree-discuss@lists.ozlabs.org/msg09472.html
Thierry
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^ permalink raw reply
* Re: [PATCH 2/3 v2] fb: udlfb: fix hang at disconnect
From: Alexander Holler @ 2013-01-29 10:35 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-kernel, linux-fbdev, Florian Tobias Schandinat,
Bernie Thompson, Steve Glendinning, stable
In-Reply-To: <51071E21.9030008@ahsoftware.de>
Am 29.01.2013 01:56, schrieb Alexander Holler:
> Am 29.01.2013 01:22, schrieb Andrew Morton:
>> On Fri, 25 Jan 2013 19:49:27 +0100
>> Alexander Holler <holler@ahsoftware.de> wrote:
>>
>>> When a device was disconnected the driver may hang at waiting for urbs it never
>>> will get. Fix this by using a timeout while waiting for the used semaphore.
>>>
>>> There is still a memory leak if a timeout happens, but at least the driver
>>> now continues his disconnect routine.
>>>
>>> ...
>>>
>>> --- a/drivers/video/udlfb.c
>>> +++ b/drivers/video/udlfb.c
>>> @@ -1832,8 +1832,9 @@ static void dlfb_free_urb_list(struct dlfb_data *dev)
>>> /* keep waiting and freeing, until we've got 'em all */
>>> while (count--) {
>>>
>>> - /* Getting interrupted means a leak, but ok at disconnect */
>>> - ret = down_interruptible(&dev->urbs.limit_sem);
>>> + /* Timeout likely occurs at disconnect (resulting in a leak) */
>>> + ret = down_timeout_killable(&dev->urbs.limit_sem,
>>> + FREE_URB_TIMEOUT);
>>> if (ret)
>>> break;
>>
>> This is rather a hack. Do you have an understanding of the underlying
>> bug? Why is the driver waiting for things which will never happen?
To add a bit more explanation:
I've experienced that bug after moving the fb-damage-handling into a
workqueue (to make the driver usable as console). This likely has
increased the possibility that an urb gets missed when the usb-stack
calls the (usb-)disconnect function of the driver. But I don't know as I
couldn't use the driver before (as fbcon) so I don't really have a
comparison.
What currently happens here is something like that:
fb -> damage -> workload which sends urb and waits for answer
device disconnect -> dlfb_usb_disconnect() -> stall (no answer to the
above urb)
I don't know why the disconnect waits for all urbs. The code looks like
it does that just to free the allocated memory. As I'm not very familiar
with the usb-stack, I would have to read up about the urb-handling to
find out how to free the memory otherwise.
As the previous comment in the code suggests that urbs already got
missed (on shutdown) before, I assume that even without my patch, which
moved the damage into a workqueue, the problem could occur which then
prevents a shutdown as there is no timeout. As I've experienced that
problem not only on disconnect, but on shutdown too (no shutdown was
possible), I have to assume, that the previous used down_interruptible()
didn't get a signal on shutdown (if the driver is used as fbcon),
therefor I consider the timeout as necessary.
Regards,
Alexander
^ permalink raw reply
* Re: [PATCH 2/3 v2] fb: udlfb: fix hang at disconnect
From: Alexander Holler @ 2013-01-29 11:11 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-kernel, linux-fbdev, Florian Tobias Schandinat,
Bernie Thompson, Steve Glendinning, stable
In-Reply-To: <5107A5ED.7020009@ahsoftware.de>
Am 29.01.2013 11:35, schrieb Alexander Holler:
> Am 29.01.2013 01:56, schrieb Alexander Holler:
>> Am 29.01.2013 01:22, schrieb Andrew Morton:
>>> On Fri, 25 Jan 2013 19:49:27 +0100
>>> Alexander Holler <holler@ahsoftware.de> wrote:
>>>
>>>> When a device was disconnected the driver may hang at waiting for
>>>> urbs it never
>>>> will get. Fix this by using a timeout while waiting for the used
>>>> semaphore.
>>>>
>>>> There is still a memory leak if a timeout happens, but at least the
>>>> driver
>>>> now continues his disconnect routine.
>>>>
>>>> ...
>>>>
>>>> --- a/drivers/video/udlfb.c
>>>> +++ b/drivers/video/udlfb.c
>>>> @@ -1832,8 +1832,9 @@ static void dlfb_free_urb_list(struct
>>>> dlfb_data *dev)
>>>> /* keep waiting and freeing, until we've got 'em all */
>>>> while (count--) {
>>>>
>>>> - /* Getting interrupted means a leak, but ok at disconnect */
>>>> - ret = down_interruptible(&dev->urbs.limit_sem);
>>>> + /* Timeout likely occurs at disconnect (resulting in a
>>>> leak) */
>>>> + ret = down_timeout_killable(&dev->urbs.limit_sem,
>>>> + FREE_URB_TIMEOUT);
>>>> if (ret)
>>>> break;
>>>
>>> This is rather a hack. Do you have an understanding of the underlying
>>> bug? Why is the driver waiting for things which will never happen?
>
> To add a bit more explanation:
>
> I've experienced that bug after moving the fb-damage-handling into a
> workqueue (to make the driver usable as console). This likely has
> increased the possibility that an urb gets missed when the usb-stack
> calls the (usb-)disconnect function of the driver. But I don't know as I
> couldn't use the driver before (as fbcon) so I don't really have a
> comparison.
>
> What currently happens here is something like that:
>
> fb -> damage -> workload which sends urb and waits for answer
> device disconnect -> dlfb_usb_disconnect() -> stall (no answer to the
> above urb)
>
> I don't know why the disconnect waits for all urbs. The code looks like
> it does that just to free the allocated memory. As I'm not very familiar
> with the usb-stack, I would have to read up about the urb-handling to
> find out how to free the memory otherwise.
>
> As the previous comment in the code suggests that urbs already got
> missed (on shutdown) before, I assume that even without my patch, which
> moved the damage into a workqueue, the problem could occur which then
> prevents a shutdown as there is no timeout. As I've experienced that
> problem not only on disconnect, but on shutdown too (no shutdown was
> possible), I have to assume, that the previous used down_interruptible()
> didn't get a signal on shutdown (if the driver is used as fbcon),
> therefor I consider the timeout as necessary.
To explain the problem on shutdown a bit further, I think the following
happens (usb and driver are statically linked and started by the kernel):
shutdown -> kill signal -> usb stack shuts down -> udlfb waits (forever)
for a kill or an urb which it doesn't get.
Maybe the sequence is different if the usb-stack and udlfb are used as a
module and/or udlfb is used only for X/fb. I'm not sure what actually
does shut down the usb-stack in such a case, but maybe more than one
kill signal might be thrown around.
Regards,
Alexander
^ permalink raw reply
* Re: [PATCH 1/4] pwm_backlight: Fix PWM levels support in non DT case
From: Peter Ujfalusi @ 2013-01-29 12:10 UTC (permalink / raw)
To: Thierry Reding
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA, Florian Tobias Schandinat,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ,
linux-doc-u79uwXL29TY76Z2rM5mHXA,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, Richard Purdie,
Andrew Morton
In-Reply-To: <20130129101709.GC16746-RM9K5IK7kjIQXX3q8xo1gnVAuStQJXxyR5q1nwbD4aMs9pC9oP6+/A@public.gmane.org>
On 01/29/2013 11:17 AM, Thierry Reding wrote:
> On Tue, Jan 29, 2013 at 09:17:04AM +0100, Peter Ujfalusi wrote:
>> On 01/28/2013 10:01 PM, Thierry Reding wrote:
>>> On Tue, Jan 22, 2013 at 02:39:53PM +0100, Peter Ujfalusi wrote:
>>>> It is expected that board files would have:
>>>> static unsigned int bl_levels[] = { 0, 50, 100, 150, 200, 250, };
>>>>
>>>> static struct platform_pwm_backlight_data bl_data = {
>>>> .levels = bl_levels,
>>>> .max_brightness = ARRAY_SIZE(bl_levels),
>>>> .dft_brightness = 4,
>>>> .pwm_period_ns = 7812500,
>>>> };
>>>>
>>>> In this case the max_brightness would be out of range in the levels array.
>>>> Decrement the received max_brightness in every case (DT or non DT) when the
>>>> levels has been provided.
>>>
>>> What's wrong with specifying .max_brightness = ARRAY_SIZE(bl_levels) - 1
>>> instead?
>>
>> There is nothing wrong with that either but IMHO it is more natural for board
>> files to use just ARRAY_SIZE(bl_levels). In this way the handling of
>> data->max_brightness among non DT and DT booted kernel is more uniform in the
>> driver itself.
>
> The .max_brightness field is defined to be the maximum value that you
> can set the brightness to. If you use .levels and set .max_brightness to
> ARRAY_SIZE() then that's no longer true because the maximum value for
> the brightness will actually be ARRAY_SIZE() - 1.
Yes, in conjunction with .levels it would be better to have .nr_levels instead
reusing the max_brightness.
> The reason why in the DT case we decrement .max_brightness is that it is
> used as a temporary variable to keep the number of levels, which
> corresponds to ARRAY_SIZE() in your example, and adjust it later on to
> match the definition. That's an implementation detail.
>
> Platform data content should be encoded properly without knowledge of
> the internal implementation.
>
>> Right now all board files are using only the .max_brightness to specify the
>> maximum value, I could not find any users of .levels in the kernel.
>
> Yes. But this is the legacy mode which should be considered deprecated.
> The reason why the concept of brightness-levels was introduced back when
> the DT bindings were created was that pretty much no hardware in
> existence actually works that way. This was a topic of discussion at the
> time when I first proposed these changes, see for example:
>
> http://www.mail-archive.com/devicetree-discuss@lists.ozlabs.org/msg09472.html
Right. Now I know the background.
However I do not agree with the conclusion. Probably it is fine in some cases
to limit the number of configurable duty cycles to have only distinct steps.
To not go too far, on my laptop I have:
# cat /sys/class/backlight/acpi_video0/max_brightness
15
# cat /sys/class/backlight/intel_backlight/max_brightness
93
In this case I would be more happier if the user space would use the
intel_backlight than the acpi_video0. I'm fine if user space decides to allow
me only 15 distinct steps on the intel_backlight but I would expect it to do
so in a way when I change the brightness in the UI it would step down or up to
the next user configurable level. Right now it uses the acpi_video0 to control
the levels which means that I have (ugly) jumps in the backlight every time I
adjust it.
In my phone and tablet all transitions between backlight levels are smooth.
This is not a case in my laptop (with exception when the backlight is set to
auto, FW controlled).
The perceived brightness change depends on the surrounding environment, you
can not say that in high level you would need less steps or you need to have
less steps in low brightness. If you in a dark room the low changes can be
observed, while the same change when you are outside in a sunny day would not
reflect the same.
Sure we could do the ramps in driver, but what are the parameters? how many
step between the two level? What is the time between the steps?
If you are about to make a product you will end up specifying all the possible
steps to provide the best user experience. So if the PWM have 127 duty cycle
you will have levels from 0, 1, 2, 3, ...., 125, 126, 127.
--
Péter
^ permalink raw reply
* Re: [PATCH 1/4] pwm_backlight: Fix PWM levels support in non DT case
From: Thierry Reding @ 2013-01-29 12:30 UTC (permalink / raw)
To: Peter Ujfalusi
Cc: Richard Purdie, Grant Likely, Rob Landley,
Florian Tobias Schandinat, Andrew Morton, devicetree-discuss,
linux-doc, linux-kernel, linux-fbdev
In-Reply-To: <5107BC2B.5080400@ti.com>
[-- Attachment #1: Type: text/plain, Size: 5076 bytes --]
On Tue, Jan 29, 2013 at 01:10:19PM +0100, Peter Ujfalusi wrote:
> On 01/29/2013 11:17 AM, Thierry Reding wrote:
> > On Tue, Jan 29, 2013 at 09:17:04AM +0100, Peter Ujfalusi wrote:
> >> On 01/28/2013 10:01 PM, Thierry Reding wrote:
> >>> On Tue, Jan 22, 2013 at 02:39:53PM +0100, Peter Ujfalusi wrote:
> >>>> It is expected that board files would have:
> >>>> static unsigned int bl_levels[] = { 0, 50, 100, 150, 200, 250, };
> >>>>
> >>>> static struct platform_pwm_backlight_data bl_data = {
> >>>> .levels = bl_levels,
> >>>> .max_brightness = ARRAY_SIZE(bl_levels),
> >>>> .dft_brightness = 4,
> >>>> .pwm_period_ns = 7812500,
> >>>> };
> >>>>
> >>>> In this case the max_brightness would be out of range in the levels array.
> >>>> Decrement the received max_brightness in every case (DT or non DT) when the
> >>>> levels has been provided.
> >>>
> >>> What's wrong with specifying .max_brightness = ARRAY_SIZE(bl_levels) - 1
> >>> instead?
> >>
> >> There is nothing wrong with that either but IMHO it is more natural for board
> >> files to use just ARRAY_SIZE(bl_levels). In this way the handling of
> >> data->max_brightness among non DT and DT booted kernel is more uniform in the
> >> driver itself.
> >
> > The .max_brightness field is defined to be the maximum value that you
> > can set the brightness to. If you use .levels and set .max_brightness to
> > ARRAY_SIZE() then that's no longer true because the maximum value for
> > the brightness will actually be ARRAY_SIZE() - 1.
>
> Yes, in conjunction with .levels it would be better to have .nr_levels instead
> reusing the max_brightness.
>
> > The reason why in the DT case we decrement .max_brightness is that it is
> > used as a temporary variable to keep the number of levels, which
> > corresponds to ARRAY_SIZE() in your example, and adjust it later on to
> > match the definition. That's an implementation detail.
> >
> > Platform data content should be encoded properly without knowledge of
> > the internal implementation.
> >
> >> Right now all board files are using only the .max_brightness to specify the
> >> maximum value, I could not find any users of .levels in the kernel.
> >
> > Yes. But this is the legacy mode which should be considered deprecated.
> > The reason why the concept of brightness-levels was introduced back when
> > the DT bindings were created was that pretty much no hardware in
> > existence actually works that way. This was a topic of discussion at the
> > time when I first proposed these changes, see for example:
> >
> > http://www.mail-archive.com/devicetree-discuss@lists.ozlabs.org/msg09472.html
>
> Right. Now I know the background.
> However I do not agree with the conclusion. Probably it is fine in some cases
> to limit the number of configurable duty cycles to have only distinct steps.
> To not go too far, on my laptop I have:
> # cat /sys/class/backlight/acpi_video0/max_brightness
> 15
> # cat /sys/class/backlight/intel_backlight/max_brightness
> 93
FWIW, I have hardware with an Intel chipset that has max_brightness
13666. That doesn't mean all of these are necessarily valid or useful.
> In this case I would be more happier if the user space would use the
> intel_backlight than the acpi_video0. I'm fine if user space decides to allow
> me only 15 distinct steps on the intel_backlight but I would expect it to do
> so in a way when I change the brightness in the UI it would step down or up to
> the next user configurable level. Right now it uses the acpi_video0 to control
> the levels which means that I have (ugly) jumps in the backlight every time I
> adjust it.
>
> In my phone and tablet all transitions between backlight levels are smooth.
> This is not a case in my laptop (with exception when the backlight is set to
> auto, FW controlled).
>
> The perceived brightness change depends on the surrounding environment, you
> can not say that in high level you would need less steps or you need to have
> less steps in low brightness. If you in a dark room the low changes can be
> observed, while the same change when you are outside in a sunny day would not
> reflect the same.
>
> Sure we could do the ramps in driver, but what are the parameters? how many
> step between the two level? What is the time between the steps?
>
> If you are about to make a product you will end up specifying all the possible
> steps to provide the best user experience. So if the PWM have 127 duty cycle
> you will have levels from 0, 1, 2, 3, ...., 125, 126, 127.
That's not true. The duty-cycle merely defines a percentage of how long
the PWM signal will be high. You can choose an arbitrary number of
subdivisions.
Since the brightness of a display isn't linearly proportional to the
duty cycle of the PWM driving it, representing that brightness by a
linear range is misleading. Furthermore some panels have regions where
the backlight isn't lit at all or where changes in the PWM duty-cycle
don't make any difference.
Thierry
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^ permalink raw reply
* Re: [PATCH 1/3] atmel_lcdfb: fix 16-bpp modes on older SOCs
From: Jean-Christophe PLAGNIOL-VILLARD @ 2013-01-29 13:54 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <1355142530-10366-2-git-send-email-jhovold@gmail.com>
On 13:28 Mon 10 Dec , Johan Hovold wrote:
> Fix regression introduced by commit 787f9fd23283 ("atmel_lcdfb: support
> 16bit BGR:565 mode, remove unsupported 15bit modes") which broke 16-bpp
> modes for older SOCs which use IBGR:555 (msb is intensity) rather
> than BGR:565.
>
> Use SOC-type to determine the pixel layout.
>
> Tested on custom at91sam9263-board.
>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Johan Hovold <jhovold@gmail.com>
> ---
> drivers/video/atmel_lcdfb.c | 22 +++++++++++++++-------
> include/video/atmel_lcdc.h | 1 +
> 2 files changed, 16 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c
> index 1505539..1f68fa6 100644
> --- a/drivers/video/atmel_lcdfb.c
> +++ b/drivers/video/atmel_lcdfb.c
> @@ -422,17 +422,22 @@ static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
> = var->bits_per_pixel;
> break;
> case 16:
> + /* Older SOCs use IBGR:555 rather than BGR:565. */
> + if (sinfo->have_intensity_bit)
> + var->green.length = 5;
> + else
> + var->green.length = 6;
> +
> if (sinfo->lcd_wiring_mode = ATMEL_LCDC_WIRING_RGB) {
> - /* RGB:565 mode */
> - var->red.offset = 11;
> + /* RGB:5X5 mode */
> + var->red.offset = var->green.length + 5;
> var->blue.offset = 0;
> } else {
> - /* BGR:565 mode */
> + /* BGR:5X5 mode */
> var->red.offset = 0;
> - var->blue.offset = 11;
> + var->blue.offset = var->green.length + 5;
> }
> var->green.offset = 5;
> - var->green.length = 6;
> var->red.length = var->blue.length = 5;
> break;
> case 32:
> @@ -679,8 +684,7 @@ static int atmel_lcdfb_setcolreg(unsigned int regno, unsigned int red,
>
> case FB_VISUAL_PSEUDOCOLOR:
> if (regno < 256) {
> - if (cpu_is_at91sam9261() || cpu_is_at91sam9263()
> - || cpu_is_at91sam9rl()) {
> + if (sinfo->have_intensity_bit) {
> /* old style I+BGR:555 */
> val = ((red >> 11) & 0x001f);
> val |= ((green >> 6) & 0x03e0);
> @@ -870,6 +874,10 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
> }
> sinfo->info = info;
> sinfo->pdev = pdev;
> + if (cpu_is_at91sam9261() || cpu_is_at91sam9263() ||
> + cpu_is_at91sam9rl()) {
> + sinfo->have_intensity_bit = true;
> + }
nack
you need to drop the cpu_is as this can only be use now for the core
use platform_device_id to indetify the IP as done on at91-i2c as we can not
detect the IP version
Best Regards,
J.
>
> strcpy(info->fix.id, sinfo->pdev->name);
> info->flags = ATMEL_LCDFB_FBINFO_DEFAULT;
> diff --git a/include/video/atmel_lcdc.h b/include/video/atmel_lcdc.h
> index 28447f1..5f0e234 100644
> --- a/include/video/atmel_lcdc.h
> +++ b/include/video/atmel_lcdc.h
> @@ -62,6 +62,7 @@ struct atmel_lcdfb_info {
> void (*atmel_lcdfb_power_control)(int on);
> struct fb_monspecs *default_monspecs;
> u32 pseudo_palette[16];
> + bool have_intensity_bit;
> };
>
> #define ATMEL_LCDC_DMABADDR1 0x00
> --
> 1.8.0
>
^ permalink raw reply
* Re: [Linaro-mm-sig] CDF discussions at FOSDEM
From: Daniel Vetter @ 2013-01-29 15:50 UTC (permalink / raw)
To: Laurent Pinchart
Cc: Linux Fbdev development list, Syrjala, Ville, dri-devel,
Linaro MM SIG, Clark, Rob
In-Reply-To: <CAKMK7uEJ+gyX1F=FqSEjmKYgqrrCUM3LgYZLCVWyq6eimWfGsQ@mail.gmail.com>
On Tue, Jan 29, 2013 at 3:19 PM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> On Tue, Jan 29, 2013 at 1:11 PM, Laurent Pinchart
> <laurent.pinchart@ideasonboard.com> wrote:
>>> DevRooms are also not supposed to open before 11:00 (which is already a
>>> massive improvement over 2011 and the years before, where i was happy
>>> to be able to put the cabling in at 12:00), and i tend to first get a
>>> nod of approval from the on-site devrooms supervisor before i go in and
>>> set up the room.
>>>
>>> So use the hackingroom this year. Things will hopefully be better next
>>> year.
>>
>> Saturday is pretty much out of question, given that most developers interested
>> in CDF will want to attend the X.org talks. I'll try to get a room for Sunday
>> then, but I'm not sure yet what time slots will be available. It would be
>> helpful if people interested in CDF discussions could tell me at what time
>> they plan to leave Brussels on Sunday.
>
> I'll stay till Monday early morning, so requirements from me. Adding a
> bunch of Intel guys who're interested, too.
Ok, in the interest of pre-heating the discussion a bit I've written down
my thoughts about display slave drivers. Adding a few more people and
lists to make sure I haven't missed anyone ...
Cheers, Daniel
--
Display Slaves
=======
A highly biased quick analysis from Daniel Vetter.
A quick discussion about the issues surrounding some common framework for
display slaves like panels, hdmi/DP/whatever encoders, ... Since these external
chips are very often reused accross different SoCs, it would be beneficial to
share slave driver code between different chipset drivers.
Caveat Emperor!
---------------
Current output types and slave encoders already have to deal with a pletoria of
special cases and strange features. To avoid ending up with something not
suitable for everyone, we should look at what's all supported already and how we
could possibly deal with those things:
- audio embedded into the display stream (hdmi/dp). x86 platforms with the HD
Audio framework rely on ELD and forwarding certain events as interrupts
through the hw between the display and audio side ...
- hdmi/dp helpers: HDMI/DP are both standardized output connectors with nice
complexity. DP is mostly about handling dp aux transactions and DPCD
registers, hdmi mostly about infoframes and how to correctly set them up from
the mode + edid.
- dpms is 4 states in drm, even more in fbdev afaict, but real hw only supports
on/off nowadays ... how should/do we care?
- Fancy modes and how to represent them. Random list of things we need to
represent somehow: broadcast/reduced rbg range for hdmi, yuv modes, different
bpc modes (and handling how this affects bandwidth/clocks, e.g. i915
auto-dithers to 6bpc on DP if there's not enough), 3D hdmi modes (patches have
floated on dri-devel for this), overscan compensation. Many of these things
link in with e.g. the helper libraries for certain outputs, e.g. discovering
DP sink capabilities or setting up the correct hdmi infoframe.
- How to expose random madness as properties, e.g. backlight controllers,
broadcast mode, enable/disable embedded audio (some screens advertise it, but
don't like it). For additional fun I expect different users of a display slave
driver to expect different set of "standardized" properties.
- Debug support: Register dumping, exposing random debugfs files, tracing.
Preferably somewhat unified to keep things sane, since most often slave
drivers are rather simple, but we expect quite a few different ones.
- Random metadata surrounding a display sink, like output type. Or flags for
support special modes (h/vsync polarity, interlaced/doublescan, pixel
doubling, ...).
- mode_fixup: Used a lot in drm-land to allow encoders to change the input mode,
e.g. for lvds encoders which can do upscaling, or if the encoder supports
progressive input with interlaced output and similar fancy stuff. See e.g. the
intel sdvo encoder chip support.
- Handling different control buses like i2c, direct access (not seen that yet),
DSI, DP aux, some other protocols.
- Handling of different display data standards like dsi (intel invented a few of
its own, I'm sure we're not the only ones).
- hpd support/polling. Depending upon desing hpd handling needs to be
cooperative between slave and master, or is a slave only thing (which means
the slave needs to be able to poke the master when something changes).
Similarly, masters need to know which slaves require output polling.
- Initializing of slave drivers: of/devicetree based, compiled-in static tables
in the driver, dynamic discovery by i2c probing, lookup through some
platform-specific firmware table (ACPI). Related is how to forward random
platform init values to the drivers from these sources (e.g. the panel fixed
modes) to the slave driver.
- get_hw_state support. One of the major point in the i915 modeset rewrite which
landed in 3.7 is that a lot of the hw state can be cross-checked with the sw
tracking. Helps tremendously in tracking down driver (writer) fumbles ;-)
- PSR/dsi command mode and how the start/stop frame dance should be handled.
- Random funny expectations around the modeset sequence, i.e. when (and how
often) the video stream should be enabled/disabled. In the worst case this
needs some serious cooperation between master and slaves. Even more fun for
trained output links like DP where a re-training and so restarting parts - or
even the complete - modeset sequence could be required to happen any time.
- There's more I'm sure, gfx hw tends to be insane ...
Wishful Thinking
----------------
Ignoring reality, let's look at what the perfect display slave framework should
achieve to be useful:
- Should be simple to share code between different master drivers - display slave
drivers tend to be boring assemblies of register definitions and banging the
right magic values into them. Which also means that we should aim for a high
level of unification so that using, understanding and debugging drivers is
easy.
- Since we expect drivers to be simple, even little amounts of
impedence-matching code can kill the benefits of the shared code. Furthermore
it should be possible to extend drivers with whatever subset of the above
feature list is required by the subsystem/driver using a slave driver. Again,
without incurring unnecessary amounts of impendance matching. Ofc, not all
users of slave drivers will be able to use all the crazy features.
Reality Check
-------------
We already have tons of different slave encoder frameworks sprinkled all over
the kernel, which support different sets of crazy features and are used by
different. Furthermore each subsystem seems to have come up with it's own way to
describe metadata like display modes, all sorts of type enums, properties,
helper functions for special output types.
Conclusions:
- Throwing away and rewriting all the existing code seems unwise, but we'll
likely need tons of existing drivers with the new framework.
- Unifying the metadata handling will be _really_ painful since it's deeply
ingrained into each driver. Not unifying it otoh will lead to colossal amounts
of impendance matching code.
- The union of all the slave features used by all the existing frameworks is
impressive, but also highly non-overlapping. Likely everyone has his own
utterly "must-have" feature.
Proposal
--------
I have to admit that I'm not too much in favour of the current CDF. It has a bit
of midlayer smell to it imo, and looks like it will make many of the mentioned
corner-case messy to enable. Also looking at things the proposed generic video
mode structure it seems to lack some features e.g. drm_mode already has. Which
does not include new insanity like 3d modes or some advanced infoframes stuff.
So instead I'll throw around a few ideas and principles:
- s/framework/helper library/ Yes, I really hate midlayers and just coming up
with a different name seems to go a long way towards saner apis.
- I think we should reduce the scope of the intial version massively and instead
increase the depth to fully cover everything. So instead of something which
covers everything of a limited use-case from discover, setup, modes handling
and mode-setting, concentrate on only one operation. The actual mode-set seems
to be the best case, since it usually involves a lot of the boring register
bashing code. The first interface version would ignore everything else
completely.
- Shot for the most powerful api for that little piece we're starting with, make
it the canonical thing. I.e. for modeset we need a video mode thing, and imo
it only makes sense if that's the native data structure for all invovled
subsystems. At least it should be the aim. Yeah, that means tons of work. Even
more important is that the new datastructure supports every feature already
support in some insane way in one of the existing subsystems. Imo if we keep
different datastructures everywhere, the impendance matching will eat up most
of the code sharing benefits.
- Since converting all invovled subsystems we should imo just forget about
fbdev. For obvious reasons I'm also leaning towards simply ditching the
drm prefix from the drm defines and using those ;-)
- I haven't used it in a driver yet, but mandating regmap (might need some
improvements) should get us decent unification between drivers. And hopefully
also an easy way to have unified debug tools. regmap already has trace points
and a few other cool things.
- We need some built-in way to drill direct paths from the master display driver
to the slave driver for the different subsystems. Jumping through hoops (or
even making it impossible) to extend drivers in funny ways would be a big step
backwards.
- Locking will be fun, especially once we start to add slave->master callbacks
(e.g. for stopping/starting the display signal, hpd interrupts, ...). As a
general rule I think we should aim for no locks in the slave driver, with the
master owning the slave and ensure exclusion with its own locks. Slaves which
use shared resources and so need locks (everything doing i2c actually) may not
call master callback functions with locks held.
Then, once we've gotten things of the ground and have some slave encoder drivers
which are actually shared between different subsystems/drivers/platforms or
whatever we can start to organically grow more common interfaces. Ime it's much
easier to simply extract decent interfaces after the fact than trying to come
up.
Now let's pour this into a more concrete form:
struct display_slave_ops {
/* modeset ops, e.g. prepare/modset/commit from drm */
};
struct display_slave {
struct display_slave_ops *ops;
void *driver_private;
};
I think even just that will be worth a lot of flames to come up with a good and
agreeable interface for everyone. It'll probably satisfactory to no one though.
Then each subsystem adds it's own magic, e.g.
struct drm_encoder_slave {
struct display_slave slave;
/* everything else which is there already and not covered by the display
* slave interface. */
};
Other subsystems/drivers like DSS would embed the struct display_slave in their
own equivalent data-structure.
So now we have the little problem that we want to have one single _slave_ driver
codebase, but it should be able to support n different interfaces and
potentially even more ways to be initialized and set up. Here's my idea how this
could be tackled:
1. Smash everything into one driver file/directory.
2. Use a common driver structure which contains pointers/members for all
possible use-cases. For each interface the driver supports, it'll allocate the
same structure and put the pointer into foo->slave.driver_private. This way
different entry points from different interfaces could use the same internal
functions since all deal with the same structure.
3. Add whatever magic is required to set up the driver for different platforms.
E.g. and of match, drm_encoder_slave i2c match and some direct function to set
up hardcoded cases could all live in the same file.
Getting the kernel Kconfig stuff right will be fun, but we should get by with
adding tons more stub functions. That might mean that an of/devicetree platform
build carries around a bit of gunk for x86 vbt matching maybe, but imo that
shouldn't ever get out of hand size-wise.
Once we have a few such shared drivers in place, and even more important,
unified that part of the subsystem using them a bit, it should be painfully
obvious which is the next piece to extract into the common display slave library
interface. After all, they'll live right next to each another in the driver
sources ;-)
Eventually we should get into the real fun part like dsi bus support or command
mode/PSR ... Those advanced things probably need to be optional.
But imo the key part is that we aim for real unification in the users of
display_slave's, so internally convert over everything to the new structures.
That should also make code-sharing much easier, so that we could move existing
helper functions to the common display helper library.
Bikesheds
---------
I.e. the boring details:
- Where to put slave drivers? I'll vote for anything which does not include
drivers/video ;-)
- Maybe we want to start with a different part than modeset, or add a bit more
on top. Though I really think we should start minimally and modesetting seemed
like the most useful piece of the puzzle.
- Naming the new interfaces. I'll have more asbestos suites on order ...
- Can we just copy the new "native" interface structs from drm, pls?
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
^ permalink raw reply
* Re: [PATCH 2/3 v2] fb: udlfb: fix hang at disconnect
From: Alexander Holler @ 2013-01-29 15:51 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-kernel, linux-fbdev, Florian Tobias Schandinat,
Bernie Thompson, Steve Glendinning, stable
In-Reply-To: <5107AE4F.9000809@ahsoftware.de>
Am 29.01.2013 12:11, schrieb Alexander Holler:
>
> To explain the problem on shutdown a bit further, I think the following
> happens (usb and driver are statically linked and started by the kernel):
>
> shutdown -> kill signal -> usb stack shuts down -> udlfb waits (forever)
> for a kill or an urb which it doesn't get.
Having a second look at what I've written above, I'm not even sure if
the kernel sends one or more fatal signals on shutdown at all. I've just
assumed it because otherwise down_interruptible() wouldn't have worked
before (it would have stalled on shutdown too (if an urb got missed),
not only on disconnect).
Sounds like an interesting question I should read about (if/when fatal
signals are issued by the kernel). ;)
> Maybe the sequence is different if the usb-stack and udlfb are used as a
> module and/or udlfb is used only for X/fb. I'm not sure what actually
> does shut down the usb-stack in such a case, but maybe more than one
> kill signal might be thrown around.
Regards,
Alexander
^ permalink raw reply
* Re: [Linaro-mm-sig] CDF discussions at FOSDEM
From: Marcus Lorentzon @ 2013-01-29 19:35 UTC (permalink / raw)
To: Daniel Vetter
Cc: Linux Fbdev development list, Syrjala, Ville,
dri-devel@lists.freedesktop.org, Linaro MM SIG, Laurent Pinchart,
Clark, Rob
In-Reply-To: <20130129155040.GR14766@phenom.ffwll.local>
On 01/29/2013 04:50 PM, Daniel Vetter wrote:
> On Tue, Jan 29, 2013 at 3:19 PM, Daniel Vetter<daniel.vetter@ffwll.ch> wrote:
> Ok, in the interest of pre-heating the discussion a bit I've written down
> my thoughts about display slave drivers. Adding a few more people and
> lists to make sure I haven't missed anyone ...
>
> Cheers, Daniel
> --
> Display Slaves
> =======
>
> A highly biased quick analysis from Daniel Vetter.
And here is my biased version as one of the initiators of the idea of CDF.
I work with ARM SoCs (ST-Ericsson) and mobile devices (DSI/DPI panels).
Of course some of these have the "PC" type of encoder devices like HDMI
and eDP or even VGA. But from what I have seen most of these encoders
are used by few different SoCs(GPUs?). And using these type of encoders
was quite straight forward from DRM encoders. My goal was to get some
common code of all the "mobile" panel encoders or "display module driver
IC"s as some call them. Instead of tens of drivers (my assumption) you
now have hundreds of drivers often using MIPI DSI/DPI/DBI or some
similar interface. And lots of new come each year. There are probably
more panel types than there are products on the market, since most
products use more than one type of panel on the same product to secure
sourcing for mass production (note multiple panels use same driver IC).
So that was the initial goal, to cover all of these, which most are
maintained per SoC/CPU out of kernel.org. If HDMI/DP etc fits in this
framework, then that is just a nice bonus.
I just wanted to give my history so we are not trying to include to many
different types of encoders without an actual need. Maybe the I2C drm
stuff is good enough for that type of encoders. But again, it would be
nice with one suit that fits all ...
I also like the idea to start out small. But if no support is added
initially for the mobile panel types. Then I think it will be hard to
get all vendors to start pushing those drivers, because the benefit of
doing so would be small. But maybe the CDF work with Linaro and Laurent
could just be a second step of adding the necessary details to your
really simple baseline. And I also favor the helpers over framework
approach but I miss a big piece which is the ops for panel drivers to
call back to display controller (the video source stuff).
Some inline comments below.
>
> A quick discussion about the issues surrounding some common framework for
> display slaves like panels, hdmi/DP/whatever encoders, ... Since these external
> chips are very often reused accross different SoCs, it would be beneficial to
> share slave driver code between different chipset drivers.
>
> Caveat Emperor!
> ---------------
>
> Current output types and slave encoders already have to deal with a pletoria of
> special cases and strange features. To avoid ending up with something not
> suitable for everyone, we should look at what's all supported already and how we
> could possibly deal with those things:
>
> - audio embedded into the display stream (hdmi/dp). x86 platforms with the HD
> Audio framework rely on ELD and forwarding certain events as interrupts
> through the hw between the display and audio side ...
I would assume any driver handling audio/video/cec like HDMI would hook
itself up as an mfd device. And one of those exposed functions would be
the CDF part. Instead of pushing everything into the "display parts". At
least that is sort of what we do today and it keeps the audio, cec and
display parts nicely separated.
> - hdmi/dp helpers: HDMI/DP are both standardized output connectors with nice
> complexity. DP is mostly about handling dp aux transactions and DPCD
> registers, hdmi mostly about infoframes and how to correctly set them up from
> the mode + edid.
Yes, it is a mess. But we have managed to hide that below a simple panel
API similar to CDF/omap so far.
> - dpms is 4 states in drm, even more in fbdev afaict, but real hw only supports
> on/off nowadays ... how should/do we care?
Agreed, they should all really go away unless someone find a valid use case.
> - Fancy modes and how to represent them. Random list of things we need to
> represent somehow: broadcast/reduced rbg range for hdmi, yuv modes, different
> bpc modes (and handling how this affects bandwidth/clocks, e.g. i915
> auto-dithers to 6bpc on DP if there's not enough), 3D hdmi modes (patches have
> floated on dri-devel for this), overscan compensation. Many of these things
> link in with e.g. the helper libraries for certain outputs, e.g. discovering
> DP sink capabilities or setting up the correct hdmi infoframe.
Are you saying drm modes doesn't support this as of today? I have not
used these types of modes in DRM yet. Maybe the common video mode
patches is a good start.
> - How to expose random madness as properties, e.g. backlight controllers,
> broadcast mode, enable/disable embedded audio (some screens advertise it, but
> don't like it). For additional fun I expect different users of a display slave
> driver to expect different set of "standardized" properties.
Some standardized properties would be nice :). Whatever is not standard
doesn't really matter.
> - Debug support: Register dumping, exposing random debugfs files, tracing.
> Preferably somewhat unified to keep things sane, since most often slave
> drivers are rather simple, but we expect quite a few different ones.
>
> - Random metadata surrounding a display sink, like output type. Or flags for
> support special modes (h/vsync polarity, interlaced/doublescan, pixel
> doubling, ...).
One thing that is needed is all the meta data related to the
control/data interface between display controller and encoder. Because
this has to be unified per interface type like DSI/DBI so the same CDF
driver can setup different display controllers. But I hope we could
split the "CDF API" (panel ops) from the control/data bus API
(host/source ops or CDF video source).
> - mode_fixup: Used a lot in drm-land to allow encoders to change the input mode,
> e.g. for lvds encoders which can do upscaling, or if the encoder supports
> progressive input with interlaced output and similar fancy stuff. See e.g. the
> intel sdvo encoder chip support.
>
> - Handling different control buses like i2c, direct access (not seen that yet),
> DSI, DP aux, some other protocols.
This is actually the place I wanted to start. With vendor specific panel
drivers using common ops to access the bus (DSI/I2C/DBI etc). Then once
we have a couple of panel drivers we could unify the API making them do
their stuff (like the current CDF ops). Or even better, maybe these two
could be made completely separate and worked on in parallel.
> - Handling of different display data standards like dsi (intel invented a few of
> its own, I'm sure we're not the only ones).
>
> - hpd support/polling. Depending upon desing hpd handling needs to be
> cooperative between slave and master, or is a slave only thing (which means
> the slave needs to be able to poke the master when something changes).
> Similarly, masters need to know which slaves require output polling.
I prefer a slave only thing forwarded to the drm encoder which I assume
would be the drm equivalent of the display slave. At least I have not
seen any need to involve the display controller in hpd (which I assume
you mean by master).
> - Initializing of slave drivers: of/devicetree based, compiled-in static tables
> in the driver, dynamic discovery by i2c probing, lookup through some
> platform-specific firmware table (ACPI). Related is how to forward random
> platform init values to the drivers from these sources (e.g. the panel fixed
> modes) to the slave driver.
I'm not that familiar with the bios/uefi world. But on our SoCs we
always have to show a splash screen from the boot loader (like bios,
usually little kernel, uboot etc). And so all probing is done by
bootloader and HW is running when kernel boot. And you are not allowed
to disrupt it either because that would yield visual glitches during
boot. So some way or the other the boot loader would need to transfer
the state to the kernel or you would have to reverse engineer the state
from hw at kernel probe.
> - get_hw_state support. One of the major point in the i915 modeset rewrite which
> landed in 3.7 is that a lot of the hw state can be cross-checked with the sw
> tracking. Helps tremendously in tracking down driver (writer) fumbles ;-)
This sounds more like a display controller feature than a display slave
feature.
> - PSR/dsi command mode and how the start/stop frame dance should be handled.
Again, a vital piece for the many mobile driver ICs. And I think we have
several sources (STE, Renesas, TI, Samsung, ...) on how to do this and
tested in many products. So I hope this could be an early step in the
evolution.
> - Random funny expectations around the modeset sequence, i.e. when (and how
> often) the video stream should be enabled/disabled. In the worst case this
> needs some serious cooperation between master and slaves. Even more fun for
> trained output links like DP where a re-training and so restarting parts - or
> even the complete - modeset sequence could be required to happen any time.
Again, we have several samples of platforms already doing this stuff. So
we should be able to get a draft pretty early. From my experience when
to enable/disable video stream could vary between versions of the same
display controller. So I think it could be pretty hairy to get a single
solution for all. Instead I think we need to leave some room for the
master/slave to decide when to enable/disable. And to be able to do this
we should try to have pretty specific ops on the slave and master. I'm
not sure prepare/modeset/commit is specific enough unless we document
what is expected to be done by the slave in each of these.
>
> - There's more I'm sure, gfx hw tends to be insane ...
Yes, and one is the chain of slaves issue that is "common" on mobile
systems. One example I have is
dispc->dsi->dsi2dsi-bridge->dsi2lvds-bridge->lvds-panel.
My proposal to hide this complexity in CDF was aggregate drivers. So
from drm there will only be one master (dispc) and one slave (dsi2dsi).
Then dsi2dsi will itself use another CDF/slave driver to talk to its
slave. This way the top master (dispc) driver never have to care about
this complexity. Whether this is possible to hide in practice we will
see ...
>
> Wishful Thinking
> ----------------
>
> Ignoring reality, let's look at what the perfect display slave framework should
> achieve to be useful:
>
> - Should be simple to share code between different master drivers - display slave
> drivers tend to be boring assemblies of register definitions and banging the
> right magic values into them. Which also means that we should aim for a high
> level of unification so that using, understanding and debugging drivers is
> easy.
>
> - Since we expect drivers to be simple, even little amounts of
> impedence-matching code can kill the benefits of the shared code. Furthermore
> it should be possible to extend drivers with whatever subset of the above
> feature list is required by the subsystem/driver using a slave driver. Again,
> without incurring unnecessary amounts of impendance matching. Ofc, not all
> users of slave drivers will be able to use all the crazy features.
This is also my fear. Which is why I wanted to start with one slave
interface at a time. And maybe even have different "API"s for differnt
type of panels. Like classic I2C encoders, DSI command mode "smart"
panels, DSI video mode, DPI ... and then do another layer of helpers in
drm encoders. That way a DSI command mode panel wouldn't have to be
forced into the same shell as a I2C HDMI encoder as they are very
different with very little overlap.
> Reality Check
> -------------
>
> We already have tons of different slave encoder frameworks sprinkled all over
> the kernel, which support different sets of crazy features and are used by
> different. Furthermore each subsystem seems to have come up with it's own way to
> describe metadata like display modes, all sorts of type enums, properties,
> helper functions for special output types.
>
> Conclusions:
>
> - Throwing away and rewriting all the existing code seems unwise, but we'll
> likely need tons of existing drivers with the new framework.
>
> - Unifying the metadata handling will be _really_ painful since it's deeply
> ingrained into each driver. Not unifying it otoh will lead to colossal amounts
> of impendance matching code.
>
> - The union of all the slave features used by all the existing frameworks is
> impressive, but also highly non-overlapping. Likely everyone has his own
> utterly "must-have" feature.
>
> Proposal
> --------
>
> I have to admit that I'm not too much in favour of the current CDF. It has a bit
> of midlayer smell to it imo, and looks like it will make many of the mentioned
> corner-case messy to enable. Also looking at things the proposed generic video
> mode structure it seems to lack some features e.g. drm_mode already has. Which
> does not include new insanity like 3d modes or some advanced infoframes stuff.
>
> So instead I'll throw around a few ideas and principles:
>
> - s/framework/helper library/ Yes, I really hate midlayers and just coming up
> with a different name seems to go a long way towards saner apis.
Me like, but I hope you agree to keep calling it CDF until it is merged.
We could call it Common Display Frelpers if you like ;)
> - I think we should reduce the scope of the intial version massively and instead
> increase the depth to fully cover everything. So instead of something which
> covers everything of a limited use-case from discover, setup, modes handling
> and mode-setting, concentrate on only one operation. The actual mode-set seems
> to be the best case, since it usually involves a lot of the boring register
> bashing code. The first interface version would ignore everything else
> completely.
To also cover and be useful to mobile panels I suggest starting with
on/off using a fixed mode initially. Because modeset is not used for
most mobile panels (they only have one mode).
> - Shot for the most powerful api for that little piece we're starting with, make
> it the canonical thing. I.e. for modeset we need a video mode thing, and imo
> it only makes sense if that's the native data structure for all invovled
> subsystems. At least it should be the aim. Yeah, that means tons of work. Even
> more important is that the new datastructure supports every feature already
> support in some insane way in one of the existing subsystems. Imo if we keep
> different datastructures everywhere, the impendance matching will eat up most
> of the code sharing benefits.
>
> - Since converting all invovled subsystems we should imo just forget about
> fbdev. For obvious reasons I'm also leaning towards simply ditching the
> drm prefix from the drm defines and using those ;-)
>
> - I haven't used it in a driver yet, but mandating regmap (might need some
> improvements) should get us decent unification between drivers. And hopefully
> also an easy way to have unified debug tools. regmap already has trace points
> and a few other cool things.
Guideline for I2C slave drivers maybe? Do we really want to enforce how
drivers are implemented when it doesn't affect the API?
Also, I don't think it fits in general for slaves. Since DSI/DBI have
not only registers but also operations you can execute using control
interface.
> - We need some built-in way to drill direct paths from the master display driver
> to the slave driver for the different subsystems. Jumping through hoops (or
> even making it impossible) to extend drivers in funny ways would be a big step
> backwards.
>
> - Locking will be fun, especially once we start to add slave->master callbacks
> (e.g. for stopping/starting the display signal, hpd interrupts, ...). As a
> general rule I think we should aim for no locks in the slave driver, with the
> master owning the slave and ensure exclusion with its own locks. Slaves which
> use shared resources and so need locks (everything doing i2c actually) may not
> call master callback functions with locks held.
Agreed, and I think we should rely on upper layers like drm as much as
possible for locking.
> Then, once we've gotten things of the ground and have some slave encoder drivers
> which are actually shared between different subsystems/drivers/platforms or
> whatever we can start to organically grow more common interfaces. Ime it's much
> easier to simply extract decent interfaces after the fact than trying to come
> up.
>
> Now let's pour this into a more concrete form:
>
> struct display_slave_ops {
> /* modeset ops, e.g. prepare/modset/commit from drm */
> };
>
> struct display_slave {
> struct display_slave_ops *ops;
> void *driver_private;
> };
>
> I think even just that will be worth a lot of flames to come up with a good and
> agreeable interface for everyone. It'll probably satisfactory to no one though.
>
> Then each subsystem adds it's own magic, e.g.
>
> struct drm_encoder_slave {
> struct display_slave slave;
>
> /* everything else which is there already and not covered by the display
> * slave interface. */
> };
I like the starting point. Hard to make it any more simple ;). But next
step would probably follow quickly. I also like the idea to have current
drivers aggregate the slave to make transition easier. CDF as it is now
is an all or nothing API. And since you don't care how slaves interact
with master (bus ops) I see the possibility still to separate "CDI
device API" and "CDF bus API". Which would allow using DSI bus API for
DSI panels and I2C bus API (or regmap) for I2C encoders instead of force
use of the video source API in all slave drivers.
> Other subsystems/drivers like DSS would embed the struct display_slave in their
> own equivalent data-structure.
>
> So now we have the little problem that we want to have one single _slave_ driver
> codebase, but it should be able to support n different interfaces and
> potentially even more ways to be initialized and set up. Here's my idea how this
> could be tackled:
>
> 1. Smash everything into one driver file/directory.
> 2. Use a common driver structure which contains pointers/members for all
> possible use-cases. For each interface the driver supports, it'll allocate the
> same structure and put the pointer into foo->slave.driver_private. This way
> different entry points from different interfaces could use the same internal
> functions since all deal with the same structure.
> 3. Add whatever magic is required to set up the driver for different platforms.
> E.g. and of match, drm_encoder_slave i2c match and some direct function to set
> up hardcoded cases could all live in the same file.
>
> Getting the kernel Kconfig stuff right will be fun, but we should get by with
> adding tons more stub functions. That might mean that an of/devicetree platform
> build carries around a bit of gunk for x86 vbt matching maybe, but imo that
> shouldn't ever get out of hand size-wise.
>
> Once we have a few such shared drivers in place, and even more important,
> unified that part of the subsystem using them a bit, it should be painfully
> obvious which is the next piece to extract into the common display slave library
> interface. After all, they'll live right next to each another in the driver
> sources ;-)
>
> Eventually we should get into the real fun part like dsi bus support or command
> mode/PSR ... Those advanced things probably need to be optional.
>
> But imo the key part is that we aim for real unification in the users of
> display_slave's, so internally convert over everything to the new structures.
> That should also make code-sharing much easier, so that we could move existing
> helper functions to the common display helper library.
What about drivers that are waiting for CDF to be pushed upstream
instead of having to push another custom panel framework? I'm talking of
my own KMS driver ... but maybe I could put most of it in staging and
move relevant parts of DSI/DPI/HDMI panel drivers to "common" slave
drivers ...
> Bikesheds
> ---------
>
> I.e. the boring details:
>
> - Where to put slave drivers? I'll vote for anything which does not include
> drivers/video ;-)
drivers/video +1, drivers/gpu -1, who came up with putting KMS under
drivers/gpu ;)
> - Maybe we want to start with a different part than modeset, or add a bit more
> on top. Though I really think we should start minimally and modesetting seemed
> like the most useful piece of the puzzle.
As suggested, start with on/off and static/fixed mode would help single
resolution LCDs. Actually that is almost all that is needed for mobile
panels and what I intended to get from CDF :)
>
> - Naming the new interfaces. I'll have more asbestos suites on order ...
Until you get them. Would it make sense to reuse the encoder name from
drm or is that to restrictive?
>
> - Can we just copy the new "native" interface structs from drm, pls?
I hope you are not talking about the helper interfaces at least ;). But
if CDF is going to be the new drm helpers of choice for
encoder/connector parts. Then it sounds like CDF would replace most of
the old helpers. It would be far to many layers with the old helpers
too. And I think I recall Jesse wanting to deprecate/remove them too.
Hopefully we could have some generic encoder/connector helper
implementations that only depend on CDF.
/BR
/Marcus
^ permalink raw reply
* Re: [PATCH 2/3 v2] fb: udlfb: fix hang at disconnect
From: Alexander Holler @ 2013-01-29 20:35 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-kernel, linux-fbdev, Florian Tobias Schandinat,
Bernie Thompson, Steve Glendinning, stable
In-Reply-To: <5107F014.4030704@ahsoftware.de>
Am 29.01.2013 16:51, schrieb Alexander Holler:
> Am 29.01.2013 12:11, schrieb Alexander Holler:
>
>>
>> To explain the problem on shutdown a bit further, I think the following
>> happens (usb and driver are statically linked and started by the kernel):
>>
>> shutdown -> kill signal -> usb stack shuts down -> udlfb waits (forever)
>> for a kill or an urb which it doesn't get.
>
> Having a second look at what I've written above, I'm not even sure if
> the kernel sends one or more fatal signals on shutdown at all. I've just
> assumed it because otherwise down_interruptible() wouldn't have worked
> before (it would have stalled on shutdown too (if an urb got missed),
> not only on disconnect).
>
> Sounds like an interesting question I should read about (if/when fatal
> signals are issued by the kernel). ;)
>
>> Maybe the sequence is different if the usb-stack and udlfb are used as a
>> module and/or udlfb is used only for X/fb. I'm not sure what actually
>> does shut down the usb-stack in such a case, but maybe more than one
>> kill signal might be thrown around.
If anyone still follows my monologue: The question was interesting
enough that I couldn't resist for long. ;)
(all pasted => format broken)
In drivers/tty/sysrq.c there is
------
static void send_sig_all(int sig)
{
struct task_struct *p;
read_lock(&tasklist_lock);
for_each_process(p) {
if (p->flags & PF_KTHREAD)
continue;
if (is_global_init(p))
continue;
do_send_sig_info(sig, SEND_SIG_FORCED, p, true);
}
read_unlock(&tasklist_lock);
}
static void sysrq_handle_term(int key)
{
send_sig_all(SIGTERM);
console_loglevel = 8;
}
(...)
static void sysrq_handle_kill(int key)
{
send_sig_all(SIGKILL);
console_loglevel = 8;
}
------
Now I've done some learning by doing (kernel 3.7.5 + some patches):
------
diff --git a/drivers/video/udlfb.c b/drivers/video/udlfb.c
index df249f3..db8a86c 100644
--- a/drivers/video/udlfb.c
+++ b/drivers/video/udlfb.c
@@ -1876,14 +1876,18 @@ static void dlfb_free_urb_list(struct dlfb_data
*dev)
unsigned long flags;
pr_notice("Freeing all render urbs\n");
+ if (current->flags & PF_KTHREAD)
+ pr_info("AHO: I'm a kernel thread\n");
/* keep waiting and freeing, until we've got 'em all */
while (count--) {
/* Timeout likely occurs at disconnect (resulting in a
leak) */
ret = down_timeout_killable(&dev->urbs.limit_sem,
FREE_URB_TIMEOUT);
- if (ret)
+ if (ret) {
+ pr_info("AHO: ret %d\n", ret);
break;
+ }
spin_lock_irqsave(&dev->urbs.lock, flags);
------
Now I've disconnected the display. And, as send_sig_all() already
suggests, the result was (besides discovering an oops in
call_timer_fn.isra (once)):
------
[ 120.963010] udlfb: AHO: I'm a kernel thread
[ 122.957024] udlfb: AHO: ret -62
------
(-62 is -ETIME)
So, if the above down_timeout_killable() is only down_interruptible(),
as in kernel 3.7.5, the box would not shutdown afterwards, because on
shutdown no signal would be send to that kernel-thread which called
dlfb_free_urb_list().
A last note: dlfb_usb_disconnect() (thus dlfb_free_urb_list()) isn't
called on shutdown if the device would still be connected. So the
problem only might happen, if the screen will be disconnected before
shutdown (and an urb gets missed). So the subject of my patch is correct. ;)
</monologue>
Regards,
Alexander
^ permalink raw reply related
* Re: [PATCH 2/3 v2] fb: udlfb: fix hang at disconnect
From: Alexander Holler @ 2013-01-29 20:56 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-kernel, linux-fbdev, Florian Tobias Schandinat,
Bernie Thompson, Steve Glendinning, stable
In-Reply-To: <5108329E.2050802@ahsoftware.de>
Am 29.01.2013 21:35, schrieb Alexander Holler:
>
> So, if the above down_timeout_killable() is only down_interruptible(),
> as in kernel 3.7.5, the box would not shutdown afterwards, because on
> shutdown no signal would be send to that kernel-thread which called
> dlfb_free_urb_list().
>
> A last note: dlfb_usb_disconnect() (thus dlfb_free_urb_list()) isn't
> called on shutdown if the device would still be connected. So the
> problem only might happen, if the screen will be disconnected before
> shutdown (and an urb gets missed). So the subject of my patch is
> correct. ;)
>
> </monologue>
Hmm, wrong, sorry, I still have something to add: As no signal arrives
at all, v1 of that patch is enough and the implementation of
down_timeout_killable() isn't necessary at all.
If there is a chance that the patch would be Acked-by by someone, I
would made a v3, replacing
+ ret = down_timeout(&dev->urbs.limit_sem, GET_URB_TIMEOUT);
in v1 with
+ ret = down_timeout(&dev->urbs.limit_sem, FREE_URB_TIMEOUT);
as this seems to be what it should be.
Regards,
Alexander
^ permalink raw reply
* Re: [Linaro-mm-sig] CDF discussions at FOSDEM
From: Daniel Vetter @ 2013-01-29 21:46 UTC (permalink / raw)
To: Marcus Lorentzon
Cc: Linux Fbdev development list, Syrjala, Ville, Daniel Vetter,
dri-devel@lists.freedesktop.org, Linaro MM SIG, Laurent Pinchart,
Clark, Rob
In-Reply-To: <51082480.9070500@stericsson.com>
On Tue, Jan 29, 2013 at 08:35:28PM +0100, Marcus Lorentzon wrote:
> On 01/29/2013 04:50 PM, Daniel Vetter wrote:
> >On Tue, Jan 29, 2013 at 3:19 PM, Daniel Vetter<daniel.vetter@ffwll.ch> wrote:
> >Ok, in the interest of pre-heating the discussion a bit I've written down
> >my thoughts about display slave drivers. Adding a few more people and
> >lists to make sure I haven't missed anyone ...
> >
> >Cheers, Daniel
> >--
> >Display Slaves
> >=======
> >
> >A highly biased quick analysis from Daniel Vetter.
> And here is my biased version as one of the initiators of the idea of CDF.
Thanks a lot for your detailed answer. Some quick replies, I need to go
through this more carefully and maybe send another mail.
> I work with ARM SoCs (ST-Ericsson) and mobile devices (DSI/DPI
> panels). Of course some of these have the "PC" type of encoder
> devices like HDMI and eDP or even VGA. But from what I have seen
> most of these encoders are used by few different SoCs(GPUs?). And
> using these type of encoders was quite straight forward from DRM
> encoders. My goal was to get some common code of all the "mobile"
> panel encoders or "display module driver IC"s as some call them.
> Instead of tens of drivers (my assumption) you now have hundreds of
> drivers often using MIPI DSI/DPI/DBI or some similar interface. And
> lots of new come each year. There are probably more panel types than
> there are products on the market, since most products use more than
> one type of panel on the same product to secure sourcing for mass
> production (note multiple panels use same driver IC).
> So that was the initial goal, to cover all of these, which most are
> maintained per SoC/CPU out of kernel.org. If HDMI/DP etc fits in
> this framework, then that is just a nice bonus.
> I just wanted to give my history so we are not trying to include to
> many different types of encoders without an actual need. Maybe the
> I2C drm stuff is good enough for that type of encoders. But again,
> it would be nice with one suit that fits all ...
> I also like the idea to start out small. But if no support is added
> initially for the mobile panel types. Then I think it will be hard
> to get all vendors to start pushing those drivers, because the
> benefit of doing so would be small. But maybe the CDF work with
> Linaro and Laurent could just be a second step of adding the
> necessary details to your really simple baseline. And I also favor
> the helpers over framework approach but I miss a big piece which is
> the ops for panel drivers to call back to display controller (the
> video source stuff).
Yeah, I think we have two main goals here for enabling code sharing for
these output devices:
1. Basic panel support, with the panel usually glued onto the board, so
squat runtime configuration required. Aim is to get the gazillion of
out-of-tree drivers merged.
2. Allowing generic output encoder slaves to be used in a bunch of SoCs in.
Summarizing my previous mail I fear that if we start with with the first
point and don't take some of the mad features required to do the 2nd one
right into account, we'll end up at a rather ugly spot.
[cut]
> >- hdmi/dp helpers: HDMI/DP are both standardized output connectors with nice
> > complexity. DP is mostly about handling dp aux transactions and DPCD
> > registers, hdmi mostly about infoframes and how to correctly set them up from
> > the mode + edid.
> Yes, it is a mess. But we have managed to hide that below a simple
> panel API similar to CDF/omap so far.
Well, my concern is that we need to expose a bunch of special properties
(both to the master driver and ultimately to userspace) which are rather
hard to shovel through a simple panel abstraction. Ime from desktop
graphics there's no limits to the insane usecases and devices people come
up with and want to plug into your machine ;-)
> >- dpms is 4 states in drm, even more in fbdev afaict, but real hw only supports
> > on/off nowadays ... how should/do we care?
> Agreed, they should all really go away unless someone find a valid use case.
> >- Fancy modes and how to represent them. Random list of things we need to
> > represent somehow: broadcast/reduced rbg range for hdmi, yuv modes, different
> > bpc modes (and handling how this affects bandwidth/clocks, e.g. i915
> > auto-dithers to 6bpc on DP if there's not enough), 3D hdmi modes (patches have
> > floated on dri-devel for this), overscan compensation. Many of these things
> > link in with e.g. the helper libraries for certain outputs, e.g. discovering
> > DP sink capabilities or setting up the correct hdmi infoframe.
> Are you saying drm modes doesn't support this as of today? I have
> not used these types of modes in DRM yet. Maybe the common video
> mode patches is a good start.
All the stuff I've mentioned is support in drm/i915 (or at least we have
patches floating around), and on a quick look at the proposed video_mode I
couldn't fit this all in. Some of the features are fully fledged out, but
I expect that we fill all the little tiny holes in the next few releases.
> >- How to expose random madness as properties, e.g. backlight controllers,
> > broadcast mode, enable/disable embedded audio (some screens advertise it, but
> > don't like it). For additional fun I expect different users of a display slave
> > driver to expect different set of "standardized" properties.
> Some standardized properties would be nice :). Whatever is not
> standard doesn't really matter.
The problem is that we have a few 100klocs of driver code lying around in
upstream, so if we switch standards there's some decent fun involved
converting things. Or we need to add conversion functions all over the
place, which seems rather ugly, too.
> >- Debug support: Register dumping, exposing random debugfs files, tracing.
> > Preferably somewhat unified to keep things sane, since most often slave
> > drivers are rather simple, but we expect quite a few different ones.
> >
> >- Random metadata surrounding a display sink, like output type. Or flags for
> > support special modes (h/vsync polarity, interlaced/doublescan, pixel
> > doubling, ...).
> One thing that is needed is all the meta data related to the
> control/data interface between display controller and encoder.
> Because this has to be unified per interface type like DSI/DBI so
> the same CDF driver can setup different display controllers. But I
> hope we could split the "CDF API" (panel ops) from the control/data
> bus API (host/source ops or CDF video source).
I guess we have two options of panels on such buses with special needs:
- either add a bunch of optional functions to the common interfaces
- or subclass the common interface/struct and add additional magic in
there, i.e.
struct dsi_slave {
struct display_slave;
struct dsi_panel_ops;
/* whatever other magic we need for dsi, e.g. callbacks to the
* source for start/stopping pixel data ... */
}
The later requires a bit more casting of struct pointers, but should be
more flexible. Ime from i915 code it's not too onereous, e.g. for encoders
we nest such C struct classes about 4 levels deep in the code: drm_encoder
-> intel_encoder -> intel_dig_encoder -> intel_dp/hdmi/ddi
So I think both approaches are doable.
> >- mode_fixup: Used a lot in drm-land to allow encoders to change the input mode,
> > e.g. for lvds encoders which can do upscaling, or if the encoder supports
> > progressive input with interlaced output and similar fancy stuff. See e.g. the
> > intel sdvo encoder chip support.
> >
> >- Handling different control buses like i2c, direct access (not seen that yet),
> > DSI, DP aux, some other protocols.
> This is actually the place I wanted to start. With vendor specific
> panel drivers using common ops to access the bus (DSI/I2C/DBI etc).
> Then once we have a couple of panel drivers we could unify the API
> making them do their stuff (like the current CDF ops). Or even
> better, maybe these two could be made completely separate and worked
> on in parallel.
Hm, so starting with some DSI interface code, similarly to how we have
i2c? tbh I have pretty much zero clue about how dsi exactly works, but
growing different parts of a common panel infrastructure sounds
intriguing.
> >- Handling of different display data standards like dsi (intel invented a few of
> > its own, I'm sure we're not the only ones).
> >
> >- hpd support/polling. Depending upon desing hpd handling needs to be
> > cooperative between slave and master, or is a slave only thing (which means
> > the slave needs to be able to poke the master when something changes).
> > Similarly, masters need to know which slaves require output polling.
> I prefer a slave only thing forwarded to the drm encoder which I
> assume would be the drm equivalent of the display slave. At least I
> have not seen any need to involve the display controller in hpd
> (which I assume you mean by master).
I've used pretty unclear definitions. Generally master is everything no
behind the slave/panel interface. Call it display driver maybe ... For
this case I don't expect that hpd involves any piece of hw on the
master/driver side, but we need to somehow forward this to the usespace
interfaces. At least in drm, dunno what other display drivers do here.
> >- Initializing of slave drivers: of/devicetree based, compiled-in static tables
> > in the driver, dynamic discovery by i2c probing, lookup through some
> > platform-specific firmware table (ACPI). Related is how to forward random
> > platform init values to the drivers from these sources (e.g. the panel fixed
> > modes) to the slave driver.
> I'm not that familiar with the bios/uefi world. But on our SoCs we
> always have to show a splash screen from the boot loader (like bios,
> usually little kernel, uboot etc). And so all probing is done by
> bootloader and HW is running when kernel boot. And you are not
> allowed to disrupt it either because that would yield visual
> glitches during boot. So some way or the other the boot loader would
> need to transfer the state to the kernel or you would have to
> reverse engineer the state from hw at kernel probe.
Actually reverse engineer the bios state from the actual hw state is what
we now do for i915 ;-) Which is why we need the ->get_hw_state callback in
some form. But that's just a result of some of the horrible things old
firmware does, it /should/ be better on newer platforms. And hopefully the
embedded ones aren't that massively screwed up ... Iirc the only current
interface exposed by ACPI lets you get at the vendor boot splash and
display it after you've taken over the hw.
> >- get_hw_state support. One of the major point in the i915 modeset rewrite which
> > landed in 3.7 is that a lot of the hw state can be cross-checked with the sw
> > tracking. Helps tremendously in tracking down driver (writer) fumbles ;-)
> This sounds more like a display controller feature than a display
> slave feature.
See above for why we have that in i915. And we do call down into slave
encoders (Intel (s)dvo standards) on older hw. Might be we won't need that
any more on SoC platforms (I do hope that's the case at least).
> >- PSR/dsi command mode and how the start/stop frame dance should be handled.
> Again, a vital piece for the many mobile driver ICs. And I think we
> have several sources (STE, Renesas, TI, Samsung, ...) on how to do
> this and tested in many products. So I hope this could be an early
> step in the evolution.
One issue with start/stop callbacks I've discussed a bit with Jani Nikula
and Rob Clark is locking rules around start/stop callbacks from the slave
to the display source. Especially how to handle fun like blocking the dsi
bus while we need to wait for the transfer window.
> >- Random funny expectations around the modeset sequence, i.e. when (and how
> > often) the video stream should be enabled/disabled. In the worst case this
> > needs some serious cooperation between master and slaves. Even more fun for
> > trained output links like DP where a re-training and so restarting parts - or
> > even the complete - modeset sequence could be required to happen any time.
> Again, we have several samples of platforms already doing this
> stuff. So we should be able to get a draft pretty early. From my
> experience when to enable/disable video stream could vary between
> versions of the same display controller. So I think it could be
> pretty hairy to get a single solution for all. Instead I think we
> need to leave some room for the master/slave to decide when to
> enable/disable. And to be able to do this we should try to have
> pretty specific ops on the slave and master. I'm not sure
> prepare/modeset/commit is specific enough unless we document what is
> expected to be done by the slave in each of these.
Well, drm/i915 killed prepare/modeset/commit ops, we now have our own
which semantics matching our hw. My concern here is mostly about fancier
display buses with link training - e.g. on DP you can't just start/stop
the pixel stream, but there's a nice dance involved to do it.
> >- There's more I'm sure, gfx hw tends to be insane ...
> Yes, and one is the chain of slaves issue that is "common" on mobile
> systems. One example I have is
> dispc->dsi->dsi2dsi-bridge->dsi2lvds-bridge->lvds-panel.
> My proposal to hide this complexity in CDF was aggregate drivers. So
> from drm there will only be one master (dispc) and one slave
> (dsi2dsi). Then dsi2dsi will itself use another CDF/slave driver to
> talk to its slave. This way the top master (dispc) driver never have
> to care about this complexity. Whether this is possible to hide in
> practice we will see ...
I think even more fun would be to replace the lvds endpoint with hdmi, and
the try to coax the infoframe control attributes down that pipeline (plus
who's responsibilty it is to do the various adjustments to the pixels).
[cut]
> >- I think we should reduce the scope of the intial version massively and instead
> > increase the depth to fully cover everything. So instead of something which
> > covers everything of a limited use-case from discover, setup, modes handling
> > and mode-setting, concentrate on only one operation. The actual mode-set seems
> > to be the best case, since it usually involves a lot of the boring register
> > bashing code. The first interface version would ignore everything else
> > completely.
> To also cover and be useful to mobile panels I suggest starting with
> on/off using a fixed mode initially. Because modeset is not used for
> most mobile panels (they only have one mode).
Would that be start/stop a frame for manual refresh or enable/disable the
display itself? Just curious what you're aiming for as the minimal useful
thing here ...
> >- Shot for the most powerful api for that little piece we're starting with, make
> > it the canonical thing. I.e. for modeset we need a video mode thing, and imo
> > it only makes sense if that's the native data structure for all invovled
> > subsystems. At least it should be the aim. Yeah, that means tons of work. Even
> > more important is that the new datastructure supports every feature already
> > support in some insane way in one of the existing subsystems. Imo if we keep
> > different datastructures everywhere, the impendance matching will eat up most
> > of the code sharing benefits.
> >
> >- Since converting all invovled subsystems we should imo just forget about
> > fbdev. For obvious reasons I'm also leaning towards simply ditching the
> > drm prefix from the drm defines and using those ;-)
> >
> >- I haven't used it in a driver yet, but mandating regmap (might need some
> > improvements) should get us decent unification between drivers. And hopefully
> > also an easy way to have unified debug tools. regmap already has trace points
> > and a few other cool things.
> Guideline for I2C slave drivers maybe? Do we really want to enforce
> how drivers are implemented when it doesn't affect the API?
> Also, I don't think it fits in general for slaves. Since DSI/DBI
> have not only registers but also operations you can execute using
> control interface.
Yeah, that was an idea for i2c guidelines. I guess if we have a different
(sub)type for DSI we could gather helpers somewhere which are useful only
for DSI. E.g. drm is in the process of growing some DP helpers shared
among a few drivers.
My idea behind being a bit more anal about standardization is that we
exect tons of these drivers, and also that lots of different SoC platforms
might share them. So trying to make them look similar and work in similar
ways (where reasonable) to help enable existing drivers on new SoCs and
debug isssue seemed like something we should discuss a bit.
> >- We need some built-in way to drill direct paths from the master display driver
> > to the slave driver for the different subsystems. Jumping through hoops (or
> > even making it impossible) to extend drivers in funny ways would be a big step
> > backwards.
> >
> >- Locking will be fun, especially once we start to add slave->master callbacks
> > (e.g. for stopping/starting the display signal, hpd interrupts, ...). As a
> > general rule I think we should aim for no locks in the slave driver, with the
> > master owning the slave and ensure exclusion with its own locks. Slaves which
> > use shared resources and so need locks (everything doing i2c actually) may not
> > call master callback functions with locks held.
> Agreed, and I think we should rely on upper layers like drm as much
> as possible for locking.
> >Then, once we've gotten things of the ground and have some slave encoder drivers
> >which are actually shared between different subsystems/drivers/platforms or
> >whatever we can start to organically grow more common interfaces. Ime it's much
> >easier to simply extract decent interfaces after the fact than trying to come
> >up.
> >
> >Now let's pour this into a more concrete form:
> >
> >struct display_slave_ops {
> > /* modeset ops, e.g. prepare/modset/commit from drm */
> >};
> >
> >struct display_slave {
> > struct display_slave_ops *ops;
> > void *driver_private;
> >};
> >
> >I think even just that will be worth a lot of flames to come up with a good and
> >agreeable interface for everyone. It'll probably satisfactory to no one though.
> >
> >Then each subsystem adds it's own magic, e.g.
> >
> >struct drm_encoder_slave {
> > struct display_slave slave;
> >
> > /* everything else which is there already and not covered by the display
> > * slave interface. */
> >};
> I like the starting point. Hard to make it any more simple ;). But
> next step would probably follow quickly. I also like the idea to
> have current drivers aggregate the slave to make transition easier.
> CDF as it is now is an all or nothing API. And since you don't care
> how slaves interact with master (bus ops) I see the possibility
> still to separate "CDI device API" and "CDF bus API". Which would
> allow using DSI bus API for DSI panels and I2C bus API (or regmap)
> for I2C encoders instead of force use of the video source API in all
> slave drivers.
I didn't follow here which pieces you'd like to cut apart along which
lines exactly ... Maybe some example structs or asci-art to help the
clueless?
Aside about the simplicity of the above: It's slightly tongue-in-check, I
expect it to be a bit feature-full ;-) Just wanted to direct the
discussion a bit into a minimal, but still useful interface, highly
extensible.
[cut]
> >But imo the key part is that we aim for real unification in the users of
> >display_slave's, so internally convert over everything to the new structures.
> >That should also make code-sharing much easier, so that we could move existing
> >helper functions to the common display helper library.
> What about drivers that are waiting for CDF to be pushed upstream
> instead of having to push another custom panel framework? I'm
> talking of my own KMS driver ... but maybe I could put most of it in
> staging and move relevant parts of DSI/DPI/HDMI panel drivers to
> "common" slave drivers ...
Hm, I think I've missed your driver drm/kms driver. Links to source? I
think reading through a drm driver using the current cdf would be nice,
that way I'm at least familiar with one part of the code ;-)
> >Bikesheds
> >---------
> >
> >I.e. the boring details:
> >
> >- Where to put slave drivers? I'll vote for anything which does not include
> > drivers/video ;-)
> drivers/video +1, drivers/gpu -1, who came up with putting KMS under
> drivers/gpu ;)
I think the main reason was to be as far away from fbdev/fbcon code as
possible ;-) Also, we have gem/ttm in drm, which is all about PU part and
not really about G ..
> >- Maybe we want to start with a different part than modeset, or add a bit more
> > on top. Though I really think we should start minimally and modesetting seemed
> > like the most useful piece of the puzzle.
> As suggested, start with on/off and static/fixed mode would help
> single resolution LCDs. Actually that is almost all that is needed
> for mobile panels and what I intended to get from CDF :)
> >
> >- Naming the new interfaces. I'll have more asbestos suites on order ...
> Until you get them. Would it make sense to reuse the encoder name
> from drm or is that to restrictive?
On a quick check drm lacks names for DSI encoders/panels, so we might want
to add those. And maybe a generic panel output type. I guess it would be
good to take my caveats list above and strike off everything we don't need
for basic dsi panel support, then figure out where to steal the
definitions from. Common definitions will be hard to come by, e.g. after
much bikesheds and deciding to use common fourcc codes for pixel layouts
drm ended up with simply adding a bunch of its own fourcc codes since the
ones negotiated with v4l didn't cut it.
> >- Can we just copy the new "native" interface structs from drm, pls?
> I hope you are not talking about the helper interfaces at least ;).
Nope, the drm helpers are not the interfaces. Ofc, if we end up with a
massively generic panel interface, we might add a few helpers to give
slave/panel drivers an easy way to opt for sane default behaviour. E.g.
handling a fixed panel mode and always returning that mode is something
which is reinvented in drm a few times ...
I probably should have written metadata structs/definitions, since that'll
be the part which could get ugly if we end up with diverging standards.
Interface functions obviously need to fit into what the hw bus at hand
requires us to do (e.g. for DSI special cases).
[Aside wrt drm helpers: With i915 we now have an imo rather nice example
that the drm crtc are really just helpers, and that it's not too hard to
come up with your own modeset infrastructure. On an established driver
codebase even.]
> But if CDF is going to be the new drm helpers of choice for
> encoder/connector parts. Then it sounds like CDF would replace most
> of the old helpers. It would be far to many layers with the old
> helpers too. And I think I recall Jesse wanting to deprecate/remove
> them too.
Rob's tilcdc driver uses the drm crtc helpers and for the i2c encoder
slaves he added a new set of helpers to easier integrate the crtc helpers
with the existing drm_encoder_slave infrastructure. The end-result looks
fairly reasonable imo.
In general I think as long as we aim for the different libraries to be
as orthogonal as possible so that drivers can pick and choose, more kinds
of helpers doesn't really sound bad. On the drm side I've recently brushed
up the crtc/output polling and fb helpers quite a bit, so drivers can now
pick&choose (and i915 does only use some of them). Similarly for other
helper ideas floating around like DSI, hdmi infoframe handling, dp aux
stuff ...
Of course I expect that we'll wrap things up into dwim() functions for all
the common cases.
> Hopefully we could have some generic encoder/connector helper
> implementations that only depend on CDF.
I'm not sure whether we should aim for that really - having a slave/panel
driver with mostly common code and a wee bit of shim code once for drm and
once for dss (or whatever else is out there) doesn't sound too horrible to
me. But I agree that at least for new code we should aim to get this right
from the start.
Cheers, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
^ permalink raw reply
* Re: [patch] backlight: s6e63m0: report ->gamma_table_count correctly
From: Andrew Morton @ 2013-01-30 1:01 UTC (permalink / raw)
To: Jingoo Han
Cc: 'Dan Carpenter', 'Inki Dae',
'Richard Purdie', 'Florian Tobias Schandinat',
linux-fbdev, kernel-janitors, linux-kernel
In-Reply-To: <00c601cdfaa2$c52d03c0$4f870b40$%han@samsung.com>
On Fri, 25 Jan 2013 11:22:06 +0900
Jingoo Han <jg1.han@samsung.com> wrote:
> On Thursday, January 24, 2013 10:45 PM, Dan Carpenter wrote
>
> CC'ed Andrew Morton, Inki Dae.
>
> >
> > gamma_table has 3 arrays which each hold MAX_GAMMA_LEVEL pointers to
> > int.
> >
> > The current code sets ->gamma_table_count to 6 on 64bit arches and to 3
> > on 32 bit arches. It should be 3 on everything.
>
> Actually, I don't know it is right.
> However, it is certain that this panel is currently used on 32 bit arches
> such as ARM SoCs.
I don't know what gamma_table_count is supposed to do. The only place
it is used is in s6e63m0_sysfs_show_gamma_table(). That function
doesn't actually show the table - it just prints out gamme_table_count.
Why is that useful?
Ho hum, the patch is clearly correct - the array stores int*'s and the
sysfs file should display "3" for all architectures. However I suspect
we could just remove the whole sysfs file and nobody would care...
^ permalink raw reply
* [RFC 0/4] Use the Common Display Framework in tegra-drm
From: Alexandre Courbot @ 2013-01-30 3:02 UTC (permalink / raw)
To: Laurent Pinchart, Thierry Reding, Stephen Warren, Mark Zhang
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-fbdev-u79uwXL29TY76Z2rM5mHXA,
linux-tegra-u79uwXL29TY76Z2rM5mHXA, gnurou-Re5JQEeQqe8AvxtiuMwx3w,
Alexandre Courbot
This series leverages the (still work-in-progress) Common Display Framework to
add panel support to the tegra-drm driver. It also adds a driver for the
CLAA101WA01A panel used on the Ventana board.
The CDF is a moving target but Tegra needs some sort of display framework and
even in its current state the CDF seems to be the best candidate. Besides, by
using the CDF from now on we hope to provide useful feedback to Laurent and the
other CDF designers.
The changes to tegra-drm are rather minimal. Panels are referenced from Tegra DC
output nodes through the "nvidia,panel" property. This property is looked up
when a display connect notification is received in order to see if it points to
the connected display entity. If it does, the entity is then used for output.
The DPMS states are then propagated to the output entity, which is then supposed
to call back into the set_stream() hook in order to enable/disable the output
stream as needed.
Although the overall design seems to work ok, a few specific issues need to be
addressed:
1) The CDF has a get_modes() hook, but this is already implemented by
tegra_connector_get_modes(). Ideally everything should be moved to the CDF hook,
but Tegra's implementation uses DRM functions to retrieve the EDID and CDF
should, AFAIK, remain DRM-agnostic.
2) There is currently no panel/backlight interaction, e.g. backlight status is
controlled through FB events, independantly from the panel state. It could make
sense to have the panel DT node reference the backlight and control it as part
of its own power on/off sequence. Right now however, a backlight device cannot
ignore FB events.
3) Probably related to 2), now the backlight's power controls are part of the
panel driver, because the pwm-backlight driver cannot control the power
regulator and enable GPIO. This means that the backlight power is not turned off
when its brightness is set to 0 through sysfs. Once again this speaks in favor
of having stronger panel/backlight interaction: for instance, the panel driver
could reference the backlight and hijack its update_status() op to replace it by
one that does the correct power sequencing before calling the original function.
This would require some extra infrastructure though. Another possibility would
be to have a dedicated backlight driver for each panel, with its own
"compatible" string.
The code is based on 3.8rc5 + Steffen's videomode patches and the CDF v2.
Alexandre Courbot (4):
video: panel: add CLAA101WA01A panel support
tegra: ventana: add display and backlight DT nodes
drm: tegra: use the Common Display Framework
tegra: enable CDF and claa101 panel
.../bindings/gpu/nvidia,tegra20-host1x.txt | 2 +
.../video/display/chunghwa,claa101wa01a.txt | 8 +
arch/arm/boot/dts/tegra20-ventana.dts | 34 +++-
arch/arm/configs/tegra_defconfig | 2 +
drivers/gpu/drm/tegra/drm.h | 16 ++
drivers/gpu/drm/tegra/output.c | 118 +++++++++++-
drivers/video/display/Kconfig | 8 +
drivers/video/display/Makefile | 1 +
drivers/video/display/panel-claa101wa01a.c | 209 +++++++++++++++++++++
9 files changed, 393 insertions(+), 5 deletions(-)
create mode 100644 Documentation/devicetree/bindings/video/display/chunghwa,claa101wa01a.txt
create mode 100644 drivers/video/display/panel-claa101wa01a.c
--
1.8.1.1
^ permalink raw reply
* [RFC 1/4] video: panel: add CLAA101WA01A panel support
From: Alexandre Courbot @ 2013-01-30 3:02 UTC (permalink / raw)
To: Laurent Pinchart, Thierry Reding, Stephen Warren, Mark Zhang
Cc: linux-kernel, linux-fbdev, linux-tegra, gnurou, Alexandre Courbot
In-Reply-To: <1359514939-15653-1-git-send-email-acourbot@nvidia.com>
Add support for the Chunghwa CLAA101WA01A display panel.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
.../video/display/chunghwa,claa101wa01a.txt | 8 +
drivers/video/display/Kconfig | 8 +
drivers/video/display/Makefile | 1 +
drivers/video/display/panel-claa101wa01a.c | 209 +++++++++++++++++++++
4 files changed, 226 insertions(+)
create mode 100644 Documentation/devicetree/bindings/video/display/chunghwa,claa101wa01a.txt
create mode 100644 drivers/video/display/panel-claa101wa01a.c
diff --git a/Documentation/devicetree/bindings/video/display/chunghwa,claa101wa01a.txt b/Documentation/devicetree/bindings/video/display/chunghwa,claa101wa01a.txt
new file mode 100644
index 0000000..cfdc7fd
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/display/chunghwa,claa101wa01a.txt
@@ -0,0 +1,8 @@
+Chunghwa CLAA101WA01A Display Panel
+
+Required properties:
+- compatible: "chunghwa,claa101wa01a"
+- pnl-supply: regulator controlling power supply to the panel
+- bl-supply: regulator controlling power supply to the backlight
+- pnl-enable-gpios: GPIO that enables the panel
+- bl-enable-gpios: GPIO that enables the backlight
diff --git a/drivers/video/display/Kconfig b/drivers/video/display/Kconfig
index 9ca2e60..6902abb 100644
--- a/drivers/video/display/Kconfig
+++ b/drivers/video/display/Kconfig
@@ -32,4 +32,12 @@ config DISPLAY_PANEL_R61517
If you are in doubt, say N.
+config DISPLAY_PANEL_CLAA101WA01A
+ tristate "Chunghwa CLAA101WA01A Display Panel"
+ select BACKLIGHT_PWM
+ ---help---
+ Support for the Chunghwa CLAA101WA01A Display Panel.
+
+ If you are in doubt, say N.
+
endif # DISPLAY_CORE
diff --git a/drivers/video/display/Makefile b/drivers/video/display/Makefile
index ec557a1..19084a2 100644
--- a/drivers/video/display/Makefile
+++ b/drivers/video/display/Makefile
@@ -2,3 +2,4 @@ obj-$(CONFIG_DISPLAY_CORE) += display-core.o
obj-$(CONFIG_DISPLAY_PANEL_DPI) += panel-dpi.o
obj-$(CONFIG_DISPLAY_PANEL_R61505) += panel-r61505.o
obj-$(CONFIG_DISPLAY_PANEL_R61517) += panel-r61517.o
+obj-$(CONFIG_DISPLAY_PANEL_CLAA101WA01A) += panel-claa101wa01a.o
diff --git a/drivers/video/display/panel-claa101wa01a.c b/drivers/video/display/panel-claa101wa01a.c
new file mode 100644
index 0000000..93ae86b
--- /dev/null
+++ b/drivers/video/display/panel-claa101wa01a.c
@@ -0,0 +1,209 @@
+/*
+ * CLAA101WA01A Display Panel
+ *
+ * Copyright (C) 2013 NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+
+#include <video/display.h>
+
+#define CLAA101WA01A_WIDTH 223
+#define CLAA101WA01A_HEIGHT 125
+
+struct panel_claa101 {
+ struct display_entity entity;
+ struct regulator *vdd_pnl;
+ struct regulator *vdd_bl;
+ /* Enable GPIOs */
+ int pnl_enable;
+ int bl_enable;
+};
+
+#define to_panel_claa101(p) container_of(p, struct panel_claa101, entity)
+
+static int panel_claa101_set_state(struct display_entity *entity,
+ enum display_entity_state state)
+{
+ struct panel_claa101 *panel = to_panel_claa101(entity);
+
+ /* OFF and STANDBY are equivalent to us */
+ if (state = DISPLAY_ENTITY_STATE_STANDBY)
+ state = DISPLAY_ENTITY_STATE_OFF;
+
+ switch (state) {
+ case DISPLAY_ENTITY_STATE_OFF:
+ case DISPLAY_ENTITY_STATE_STANDBY:
+ if (entity->source)
+ display_entity_set_stream(entity->source,
+ DISPLAY_ENTITY_STREAM_STOPPED);
+
+ /* TODO error checking? */
+ gpio_set_value_cansleep(panel->bl_enable, 0);
+ usleep_range(10000, 10000);
+ regulator_disable(panel->vdd_bl);
+ usleep_range(200000, 200000);
+ gpio_set_value_cansleep(panel->pnl_enable, 0);
+ regulator_disable(panel->vdd_pnl);
+ break;
+
+ case DISPLAY_ENTITY_STATE_ON:
+ regulator_enable(panel->vdd_pnl);
+ gpio_set_value_cansleep(panel->pnl_enable, 1);
+ usleep_range(200000, 200000);
+ regulator_enable(panel->vdd_bl);
+ usleep_range(10000, 10000);
+ gpio_set_value_cansleep(panel->bl_enable, 1);
+
+ if (entity->source)
+ display_entity_set_stream(entity->source,
+ DISPLAY_ENTITY_STREAM_CONTINUOUS);
+ break;
+ }
+
+ return 0;
+}
+
+static int panel_claa101_get_modes(struct display_entity *entity,
+ const struct videomode **modes)
+{
+ /* TODO get modes from EDID? */
+ return 0;
+}
+
+static int panel_claa101_get_size(struct display_entity *entity,
+ unsigned int *width, unsigned int *height)
+{
+ *width = CLAA101WA01A_WIDTH;
+ *height = CLAA101WA01A_HEIGHT;
+
+ return 0;
+}
+
+static int panel_claa101_get_params(struct display_entity *entity,
+ struct display_entity_interface_params *params)
+{
+ return 0;
+}
+
+static const struct display_entity_control_ops panel_claa101_control_ops = {
+ .set_state = panel_claa101_set_state,
+ .get_modes = panel_claa101_get_modes,
+ .get_size = panel_claa101_get_size,
+ .get_params = panel_claa101_get_params,
+};
+
+static int __init panel_claa101_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct panel_claa101 *panel;
+ int err;
+
+ panel = devm_kzalloc(dev, sizeof(*panel), GFP_KERNEL);
+ if (!panel)
+ return -ENOMEM;
+
+ panel->vdd_pnl = devm_regulator_get(dev, "pnl");
+ if (IS_ERR(panel->vdd_pnl)) {
+ dev_err(dev, "cannot get vdd regulator\n");
+ return PTR_ERR(panel->vdd_pnl);
+ }
+
+ panel->vdd_bl = devm_regulator_get(dev, "bl");
+ if (IS_ERR(panel->vdd_bl)) {
+ dev_err(dev, "cannot get bl regulator\n");
+ return PTR_ERR(panel->vdd_bl);
+ }
+
+ err = of_get_named_gpio(dev->of_node, "pnl-enable-gpios", 0);
+ if (err < 0) {
+ dev_err(dev, "cannot find panel enable GPIO!\n");
+ return err;
+ }
+ panel->pnl_enable = err;
+ err = devm_gpio_request_one(dev, panel->pnl_enable,
+ GPIOF_DIR_OUT | GPIOF_INIT_LOW, "panel");
+ if (err < 0) {
+ dev_err(dev, "cannot acquire panel enable GPIO!\n");
+ return err;
+ }
+
+ err = of_get_named_gpio(dev->of_node, "bl-enable-gpios", 0);
+ if (err < 0) {
+ dev_err(dev, "cannot find backlight enable GPIO!\n");
+ return err;
+ }
+ panel->bl_enable = err;
+ err = devm_gpio_request_one(dev, panel->bl_enable,
+ GPIOF_DIR_OUT | GPIOF_INIT_LOW, "backlight");
+ if (err < 0) {
+ dev_err(dev, "cannot acquire backlight enable GPIO!\n");
+ return err;
+ }
+
+ panel->entity.dev = dev;
+ panel->entity.ops.ctrl = &panel_claa101_control_ops;
+ err = display_entity_register(&panel->entity);
+ if (err < 0)
+ return err;
+
+ platform_set_drvdata(pdev, panel);
+
+ dev_info(dev, "%s successful\n", __func__);
+
+ return 0;
+}
+
+static int __exit panel_claa101_remove(struct platform_device *pdev)
+{
+ struct panel_claa101 *panel = platform_get_drvdata(pdev);
+
+ display_entity_unregister(&panel->entity);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static struct of_device_id panel_claa101_of_match[] = {
+ { .compatible = "chunghwa,claa101wa01a", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
+#else
+#endif
+
+static const struct dev_pm_ops panel_claa101_dev_pm_ops = {
+};
+
+static struct platform_driver panel_claa101_driver = {
+ .probe = panel_claa101_probe,
+ .remove = panel_claa101_remove,
+ .driver = {
+ .name = "panel_claa101wa01a",
+ .owner = THIS_MODULE,
+#ifdef CONFIG_PM
+ .pm = &panel_claa101_dev_pm_ops,
+#endif
+#ifdef CONFIG_OF
+ .of_match_table = of_match_ptr(panel_claa101_of_match),
+#endif
+ },
+};
+
+module_platform_driver(panel_claa101_driver);
+
+MODULE_AUTHOR("Alexandre Courbot <acourbot@nvidia.com>");
+MODULE_DESCRIPTION("Chunghwa CLAA101WA01A Display Panel");
+MODULE_LICENSE("GPL");
--
1.8.1.1
^ permalink raw reply related
* [RFC 2/4] tegra: ventana: add display and backlight DT nodes
From: Alexandre Courbot @ 2013-01-30 3:02 UTC (permalink / raw)
To: Laurent Pinchart, Thierry Reding, Stephen Warren, Mark Zhang
Cc: linux-kernel, linux-fbdev, linux-tegra, gnurou, Alexandre Courbot
In-Reply-To: <1359514939-15653-1-git-send-email-acourbot@nvidia.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
arch/arm/boot/dts/tegra20-ventana.dts | 34 +++++++++++++++++++++++++++++++---
1 file changed, 31 insertions(+), 3 deletions(-)
diff --git a/arch/arm/boot/dts/tegra20-ventana.dts b/arch/arm/boot/dts/tegra20-ventana.dts
index adc4754..48f4e6d 100644
--- a/arch/arm/boot/dts/tegra20-ventana.dts
+++ b/arch/arm/boot/dts/tegra20-ventana.dts
@@ -10,6 +10,16 @@
reg = <0x00000000 0x40000000>;
};
+ host1x {
+ dc@54200000 {
+ rgb {
+ status = "okay";
+ nvidia,ddc-i2c-bus = <&lcd_ddc>;
+ nvidia,panel = <&panel>;
+ };
+ };
+ };
+
pinmux {
pinctrl-names = "default";
pinctrl-0 = <&state_default>;
@@ -341,7 +351,7 @@
#size-cells = <0>;
};
- i2c@1 {
+ lcd_ddc: i2c@1 {
reg = <1>;
#address-cells = <1>;
#size-cells = <0>;
@@ -516,6 +526,24 @@
bus-width = <8>;
};
+ backlight: backlight {
+ compatible = "pwm-backlight";
+ pwms = <&pwm 2 5000000>;
+
+ brightness-levels = <0 16 32 48 64 80 96 112 128 144 160 176 192 208 224 240 255>;
+ default-brightness-level = <10>;
+ };
+
+ panel: panel {
+ compatible = "chunghwa,claa101wa01a";
+
+ pnl-supply = <&vdd_pnl_reg>;
+ pnl-enable-gpios = <&gpio 10 0>;
+
+ bl-supply = <&vdd_bl_reg>;
+ bl-enable-gpios = <&gpio 28 0>;
+ };
+
regulators {
compatible = "simple-bus";
#address-cells = <1>;
@@ -549,7 +577,7 @@
enable-active-high;
};
- regulator@3 {
+ vdd_pnl_reg: regulator@3 {
compatible = "regulator-fixed";
reg = <3>;
regulator-name = "vdd_pnl";
@@ -559,7 +587,7 @@
enable-active-high;
};
- regulator@4 {
+ vdd_bl_reg: regulator@4 {
compatible = "regulator-fixed";
reg = <4>;
regulator-name = "vdd_bl";
--
1.8.1.1
^ permalink raw reply related
* [RFC 3/4] drm: tegra: use the Common Display Framework
From: Alexandre Courbot @ 2013-01-30 3:02 UTC (permalink / raw)
To: Laurent Pinchart, Thierry Reding, Stephen Warren, Mark Zhang
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-fbdev-u79uwXL29TY76Z2rM5mHXA,
linux-tegra-u79uwXL29TY76Z2rM5mHXA, gnurou-Re5JQEeQqe8AvxtiuMwx3w,
Alexandre Courbot
In-Reply-To: <1359514939-15653-1-git-send-email-acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
Make the tegra-drm driver use the Common Display Framework, letting it
control the panel state according to the DPMS status.
A "nvidia,panel" property is added to the output node of the Tegra DC
that references the panel connected to a given output.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
.../bindings/gpu/nvidia,tegra20-host1x.txt | 2 +
drivers/gpu/drm/tegra/drm.h | 16 +++
drivers/gpu/drm/tegra/output.c | 118 ++++++++++++++++++++-
3 files changed, 134 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt b/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
index b4fa934..9c65e8e 100644
--- a/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
+++ b/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
@@ -67,6 +67,7 @@ of the following host1x client modules:
- nvidia,ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing
- nvidia,hpd-gpio: specifies a GPIO used for hotplug detection
- nvidia,edid: supplies a binary EDID blob
+ - nvidia,panel: phandle of a display entity connected to this output
- hdmi: High Definition Multimedia Interface
@@ -81,6 +82,7 @@ of the following host1x client modules:
- nvidia,ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing
- nvidia,hpd-gpio: specifies a GPIO used for hotplug detection
- nvidia,edid: supplies a binary EDID blob
+ - nvidia,panel: phandle of a display entity connected to this output
- tvo: TV encoder output
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index 741b5dc..5e63c56 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -17,6 +17,7 @@
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_fb_cma_helper.h>
#include <drm/drm_fixed.h>
+#include <video/display.h>
struct tegra_framebuffer {
struct drm_framebuffer base;
@@ -147,6 +148,9 @@ struct tegra_output {
struct drm_encoder encoder;
struct drm_connector connector;
+ struct display_entity this;
+ struct display_entity *output;
+ struct display_entity_notifier display_notifier;
};
static inline struct tegra_output *encoder_to_output(struct drm_encoder *e)
@@ -159,6 +163,18 @@ static inline struct tegra_output *connector_to_output(struct drm_connector *c)
return container_of(c, struct tegra_output, connector);
}
+static inline
+struct tegra_output *display_entity_to_output(struct display_entity *e)
+{
+ return container_of(e, struct tegra_output, this);
+}
+
+static inline struct tegra_output *
+display_notifier_to_output(struct display_entity_notifier *n)
+{
+ return container_of(n, struct tegra_output, display_notifier);
+}
+
static inline int tegra_output_enable(struct tegra_output *output)
{
if (output && output->ops && output->ops->enable)
diff --git a/drivers/gpu/drm/tegra/output.c b/drivers/gpu/drm/tegra/output.c
index 8140fc6..d5bf37a 100644
--- a/drivers/gpu/drm/tegra/output.c
+++ b/drivers/gpu/drm/tegra/output.c
@@ -105,6 +105,29 @@ static const struct drm_encoder_funcs encoder_funcs = {
static void tegra_encoder_dpms(struct drm_encoder *encoder, int mode)
{
+ struct tegra_output *output = encoder_to_output(encoder);
+ enum display_entity_state state;
+
+ if (!output->output)
+ return;
+
+ switch (mode) {
+ case DRM_MODE_DPMS_ON:
+ state = DISPLAY_ENTITY_STATE_ON;
+ break;
+ case DRM_MODE_DPMS_STANDBY:
+ case DRM_MODE_DPMS_SUSPEND:
+ state = DISPLAY_ENTITY_STATE_STANDBY;
+ break;
+ case DRM_MODE_DPMS_OFF:
+ state = DISPLAY_ENTITY_STATE_OFF;
+ break;
+ default:
+ dev_warn(output->dev, "unknown DPMS state, ignoring\n");
+ return;
+ }
+
+ display_entity_set_state(output->output, state);
}
static bool tegra_encoder_mode_fixup(struct drm_encoder *encoder,
@@ -129,9 +152,14 @@ static void tegra_encoder_mode_set(struct drm_encoder *encoder,
struct tegra_output *output = encoder_to_output(encoder);
int err;
- err = tegra_output_enable(output);
+ if (output->output)
+ err = display_entity_set_state(output->output,
+ DISPLAY_ENTITY_STATE_ON);
+ else
+ err = tegra_output_enable(output);
+
if (err < 0)
- dev_err(encoder->dev->dev, "tegra_output_enable(): %d\n", err);
+ dev_err(encoder->dev->dev, "cannot enable output: %d\n", err);
}
static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
@@ -185,6 +213,69 @@ int tegra_output_parse_dt(struct tegra_output *output)
return 0;
}
+static int display_notify_callback(struct display_entity_notifier *notifier,
+ struct display_entity *entity, int event)
+{
+ struct tegra_output *output = display_notifier_to_output(notifier);
+ struct device_node *pnode;
+
+ switch (event) {
+ case DISPLAY_ENTITY_NOTIFIER_CONNECT:
+ if (output->output)
+ break;
+
+ pnode = of_parse_phandle(output->of_node, "nvidia,panel", 0);
+ if (!pnode)
+ break;
+
+ if (entity->dev && entity->dev->of_node = pnode) {
+ dev_dbg(output->dev, "connecting panel\n");
+ output->output = display_entity_get(entity);
+ display_entity_connect(&output->this, output->output);
+ }
+ of_node_put(pnode);
+
+ break;
+
+ case DISPLAY_ENTITY_NOTIFIER_DISCONNECT:
+ if (!output->output || output->output != entity)
+ break;
+
+ dev_dbg(output->dev, "disconnecting panel\n");
+ display_entity_disconnect(&output->this, output->output);
+ output->output = NULL;
+ display_entity_put(&output->this);
+
+ break;
+
+ default:
+ dev_dbg(output->dev, "unhandled display event\n");
+ break;
+ }
+
+ return 0;
+}
+
+static int tegra_output_set_stream(struct display_entity *entity,
+ enum display_entity_stream_state state)
+{
+ struct tegra_output *output = display_entity_to_output(entity);
+
+ switch (state) {
+ case DISPLAY_ENTITY_STATE_OFF:
+ case DISPLAY_ENTITY_STATE_STANDBY:
+ return output->ops->disable(output);
+ case DISPLAY_ENTITY_STATE_ON:
+ return output->ops->enable(output);
+ }
+
+ return 0;
+}
+
+static struct display_entity_video_ops tegra_output_video_ops = {
+ .set_stream = tegra_output_set_stream,
+};
+
int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
{
int connector, encoder, err;
@@ -250,6 +341,23 @@ int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
output->encoder.possible_crtcs = 0x3;
+ /* register display entity */
+ memset(&output->this, 0, sizeof(output->this));
+ output->this.dev = drm->dev;
+ output->this.ops.video = &tegra_output_video_ops;
+ err = display_entity_register(&output->this);
+ if (err) {
+ dev_err(output->dev, "cannot register display entity\n");
+ return err;
+ }
+
+ /* register display notifier */
+ output->display_notifier.dev = NULL;
+ output->display_notifier.notify = display_notify_callback;
+ err = display_entity_register_notifier(&output->display_notifier);
+ if (err)
+ return err;
+
return 0;
free_hpd:
@@ -260,6 +368,12 @@ free_hpd:
int tegra_output_exit(struct tegra_output *output)
{
+ if (output->output)
+ display_entity_put(output->output);
+
+ display_entity_unregister_notifier(&output->display_notifier);
+ display_entity_unregister(&output->this);
+
if (gpio_is_valid(output->hpd_gpio)) {
free_irq(output->hpd_irq, output);
gpio_free(output->hpd_gpio);
--
1.8.1.1
^ permalink raw reply related
* [RFC 4/4] tegra: enable CDF and claa101 panel
From: Alexandre Courbot @ 2013-01-30 3:02 UTC (permalink / raw)
To: Laurent Pinchart, Thierry Reding, Stephen Warren, Mark Zhang
Cc: linux-kernel, linux-fbdev, linux-tegra, gnurou, Alexandre Courbot
In-Reply-To: <1359514939-15653-1-git-send-email-acourbot@nvidia.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
arch/arm/configs/tegra_defconfig | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/configs/tegra_defconfig b/arch/arm/configs/tegra_defconfig
index a7827fd..6da0de2 100644
--- a/arch/arm/configs/tegra_defconfig
+++ b/arch/arm/configs/tegra_defconfig
@@ -150,6 +150,8 @@ CONFIG_BACKLIGHT_LCD_SUPPORT=y
CONFIG_BACKLIGHT_CLASS_DEVICE=y
# CONFIG_BACKLIGHT_GENERIC is not set
CONFIG_BACKLIGHT_PWM=y
+CONFIG_DISPLAY_CORE=y
+CONFIG_DISPLAY_PANEL_CLAA101WA01A=y
CONFIG_FRAMEBUFFER_CONSOLE=y
CONFIG_LOGO=y
CONFIG_SOUND=y
--
1.8.1.1
^ permalink raw reply related
* [PATCH] pwm-backlight: handle BL_CORE_FBBLANK state
From: Alexandre Courbot @ 2013-01-30 6:19 UTC (permalink / raw)
To: Thierry Reding, Richard Purdie
Cc: linux-kernel, linux-fbdev, gnurou, Alexandre Courbot
According to include/linux/backlight.h, the fb_blank field is to be
removed and blank status should preferably be set by setting the
BL_CORE_FBBLANK bit of the state field. This patch ensures this
condition is also taken into account when updating the backlight state.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
drivers/video/backlight/pwm_bl.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 069983c..4af6d13 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -41,10 +41,9 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
int brightness = bl->props.brightness;
int max = bl->props.max_brightness;
- if (bl->props.power != FB_BLANK_UNBLANK)
- brightness = 0;
-
- if (bl->props.fb_blank != FB_BLANK_UNBLANK)
+ if (bl->props.power != FB_BLANK_UNBLANK ||
+ bl->props.fb_blank != FB_BLANK_UNBLANK ||
+ bl->props.state & BL_CORE_FBBLANK)
brightness = 0;
if (pb->notify)
--
1.8.1.2
^ permalink raw reply related
* Re: [RFC 3/4] drm: tegra: use the Common Display Framework
From: Mark Zhang @ 2013-01-30 6:50 UTC (permalink / raw)
To: Alexandre Courbot
Cc: Laurent Pinchart, Thierry Reding, Stephen Warren, Mark Zhang,
linux-kernel-u79uwXL29TY76Z2rM5mHXA,
linux-fbdev-u79uwXL29TY76Z2rM5mHXA,
linux-tegra-u79uwXL29TY76Z2rM5mHXA, gnurou-Re5JQEeQqe8AvxtiuMwx3w
In-Reply-To: <1359514939-15653-4-git-send-email-acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
On 01/30/2013 11:02 AM, Alexandre Courbot wrote:
> Make the tegra-drm driver use the Common Display Framework, letting it
> control the panel state according to the DPMS status.
>
> A "nvidia,panel" property is added to the output node of the Tegra DC
> that references the panel connected to a given output.
>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
[...]
> diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
> index 741b5dc..5e63c56 100644
> --- a/drivers/gpu/drm/tegra/drm.h
> +++ b/drivers/gpu/drm/tegra/drm.h
> @@ -17,6 +17,7 @@
> #include <drm/drm_gem_cma_helper.h>
> #include <drm/drm_fb_cma_helper.h>
> #include <drm/drm_fixed.h>
> +#include <video/display.h>
>
> struct tegra_framebuffer {
> struct drm_framebuffer base;
> @@ -147,6 +148,9 @@ struct tegra_output {
>
> struct drm_encoder encoder;
> struct drm_connector connector;
> + struct display_entity this;
> + struct display_entity *output;
Could you pick up a somewhat meaningful name? You know, there are too
many variables with name "drm/connector/output/encoder"... :)
> + struct display_entity_notifier display_notifier;
> };
>
[...]
> +static int display_notify_callback(struct display_entity_notifier *notifier,
> + struct display_entity *entity, int event)
> +{
> + struct tegra_output *output = display_notifier_to_output(notifier);
> + struct device_node *pnode;
> +
> + switch (event) {
> + case DISPLAY_ENTITY_NOTIFIER_CONNECT:
> + if (output->output)
> + break;
> +
> + pnode = of_parse_phandle(output->of_node, "nvidia,panel", 0);
> + if (!pnode)
> + break;
> +
> + if (entity->dev && entity->dev->of_node = pnode) {
> + dev_dbg(output->dev, "connecting panel\n");
> + output->output = display_entity_get(entity);
> + display_entity_connect(&output->this, output->output);
> + }
> + of_node_put(pnode);
> +
> + break;
> +
> + case DISPLAY_ENTITY_NOTIFIER_DISCONNECT:
> + if (!output->output || output->output != entity)
> + break;
> +
> + dev_dbg(output->dev, "disconnecting panel\n");
> + display_entity_disconnect(&output->this, output->output);
> + output->output = NULL;
> + display_entity_put(&output->this);
No "display_entity_get" for "output->this", so I don't think we need
"display_entity_put" here. If you register this entity with "release"
callback and you wanna release "output->this", call the "release"
function manually.
Only when you have "display_entity_get", use "display_entity_put" to
release.
> +
> + break;
> +
> + default:
> + dev_dbg(output->dev, "unhandled display event\n");
> + break;
> + }
> +
> + return 0;
> +}
> +
[...]
> int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
> {
> int connector, encoder, err;
> @@ -250,6 +341,23 @@ int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
>
> output->encoder.possible_crtcs = 0x3;
>
> + /* register display entity */
> + memset(&output->this, 0, sizeof(output->this));
> + output->this.dev = drm->dev;
Use "output->dev" here. Actually the device you wanna register it to
display entity is the "encoder"(in drm terms), not "drm->dev". If we use
"drm->dev" here, we will have all same device for all encoders(HDMI,
DSI...).
> + output->this.ops.video = &tegra_output_video_ops;
> + err = display_entity_register(&output->this);
> + if (err) {
> + dev_err(output->dev, "cannot register display entity\n");
> + return err;
> + }
> +
> + /* register display notifier */
> + output->display_notifier.dev = NULL;
Set "display_notifier.dev" to NULL makes we have to compare with every
display entity, just like what you do in "display_notify_callback":
entity->dev && entity->dev->of_node = pnode
So can we get the "struct device *" of panel here? Seems currently the
"of" framework doesn't allow "device_node -> device".
> + output->display_notifier.notify = display_notify_callback;
> + err = display_entity_register_notifier(&output->display_notifier);
> + if (err)
> + return err;
> +
> return 0;
>
> free_hpd:
> @@ -260,6 +368,12 @@ free_hpd:
>
> int tegra_output_exit(struct tegra_output *output)
> {
> + if (output->output)
> + display_entity_put(output->output);
> +
> + display_entity_unregister_notifier(&output->display_notifier);
> + display_entity_unregister(&output->this);
> +
> if (gpio_is_valid(output->hpd_gpio)) {
> free_irq(output->hpd_irq, output);
> gpio_free(output->hpd_gpio);
>
^ permalink raw reply
* Re: [RFC 3/4] drm: tegra: use the Common Display Framework
From: Alex Courbot @ 2013-01-30 7:01 UTC (permalink / raw)
To: Mark Zhang
Cc: Laurent Pinchart, Thierry Reding, Stephen Warren, Mark Zhang,
linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org,
linux-tegra@vger.kernel.org, gnurou@gmail.com
In-Reply-To: <5108C298.1000500@gmail.com>
On 01/30/2013 03:50 PM, Mark Zhang wrote:
>> @@ -147,6 +148,9 @@ struct tegra_output {
>>
>> struct drm_encoder encoder;
>> struct drm_connector connector;
>> + struct display_entity this;
>> + struct display_entity *output;
>
> Could you pick up a somewhat meaningful name? You know, there are too
> many variables with name "drm/connector/output/encoder"... :)
Well, it's supposed to be abstract. From the CDF point of view it could
be anything besides a panel. I know this makes it an output of an
output, but I can't think of anything better right now.
>> + if (entity->dev && entity->dev->of_node = pnode) {
>> + dev_dbg(output->dev, "connecting panel\n");
>> + output->output = display_entity_get(entity);
>> + display_entity_connect(&output->this, output->output);
>> + }
>> + of_node_put(pnode);
>> +
>> + break;
>> +
>> + case DISPLAY_ENTITY_NOTIFIER_DISCONNECT:
>> + if (!output->output || output->output != entity)
>> + break;
>> +
>> + dev_dbg(output->dev, "disconnecting panel\n");
>> + display_entity_disconnect(&output->this, output->output);
>> + output->output = NULL;
>> + display_entity_put(&output->this);
>
> No "display_entity_get" for "output->this", so I don't think we need
> "display_entity_put" here. If you register this entity with "release"
> callback and you wanna release "output->this", call the "release"
> function manually.
Oh, this was supposed to be called on output->output actually, to
balance the display_entity_get() of the connect event. Thanks for
catching this.
>> + /* register display entity */
>> + memset(&output->this, 0, sizeof(output->this));
>> + output->this.dev = drm->dev;
>
> Use "output->dev" here. Actually the device you wanna register it to
> display entity is the "encoder"(in drm terms), not "drm->dev". If we use
> "drm->dev" here, we will have all same device for all encoders(HDMI,
> DSI...).
Yes, that's absolutely right.
>> + /* register display notifier */
>> + output->display_notifier.dev = NULL;
>
> Set "display_notifier.dev" to NULL makes we have to compare with every
> display entity, just like what you do in "display_notify_callback":
>
> entity->dev && entity->dev->of_node = pnode
>
> So can we get the "struct device *" of panel here? Seems currently the
> "of" framework doesn't allow "device_node -> device".
Nope. AFAICT the device might not be instanciated at this point. We
become aware of it for the first time in the callback function. We also
don't want to defer probing until the panel is parsed first, since the
panel might also depend on resources of the display device.
Thanks,
Alex.
^ permalink raw reply
* Re: [RFC 1/4] video: panel: add CLAA101WA01A panel support
From: Mark Zhang @ 2013-01-30 7:20 UTC (permalink / raw)
To: Alexandre Courbot
Cc: Laurent Pinchart, Thierry Reding, Stephen Warren, Mark Zhang,
linux-kernel, linux-fbdev, linux-tegra, gnurou
In-Reply-To: <1359514939-15653-2-git-send-email-acourbot@nvidia.com>
On 01/30/2013 11:02 AM, Alexandre Courbot wrote:
> Add support for the Chunghwa CLAA101WA01A display panel.
>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
[...]
> +
> +#include <video/display.h>
> +
> +#define CLAA101WA01A_WIDTH 223
> +#define CLAA101WA01A_HEIGHT 125
If I remember correct, the physical size of the panel can be fetched in
EDID. If this is correct, we don't have to hard-code here.
> +
> +struct panel_claa101 {
> + struct display_entity entity;
> + struct regulator *vdd_pnl;
> + struct regulator *vdd_bl;
> + /* Enable GPIOs */
> + int pnl_enable;
> + int bl_enable;
> +};
> +
> +#define to_panel_claa101(p) container_of(p, struct panel_claa101, entity)
> +
> +static int panel_claa101_set_state(struct display_entity *entity,
> + enum display_entity_state state)
> +{
> + struct panel_claa101 *panel = to_panel_claa101(entity);
> +
> + /* OFF and STANDBY are equivalent to us */
> + if (state = DISPLAY_ENTITY_STATE_STANDBY)
> + state = DISPLAY_ENTITY_STATE_OFF;
Do we need this? The "switch" below handles the same thing already.
> +
> + switch (state) {
> + case DISPLAY_ENTITY_STATE_OFF:
> + case DISPLAY_ENTITY_STATE_STANDBY:
> + if (entity->source)
> + display_entity_set_stream(entity->source,
> + DISPLAY_ENTITY_STREAM_STOPPED);
> +
> + /* TODO error checking? */
> + gpio_set_value_cansleep(panel->bl_enable, 0);
> + usleep_range(10000, 10000);
> + regulator_disable(panel->vdd_bl);
> + usleep_range(200000, 200000);
> + gpio_set_value_cansleep(panel->pnl_enable, 0);
> + regulator_disable(panel->vdd_pnl);
> + break;
> +
> + case DISPLAY_ENTITY_STATE_ON:
> + regulator_enable(panel->vdd_pnl);
> + gpio_set_value_cansleep(panel->pnl_enable, 1);
> + usleep_range(200000, 200000);
> + regulator_enable(panel->vdd_bl);
> + usleep_range(10000, 10000);
> + gpio_set_value_cansleep(panel->bl_enable, 1);
> +
> + if (entity->source)
> + display_entity_set_stream(entity->source,
> + DISPLAY_ENTITY_STREAM_CONTINUOUS);
> + break;
> + }
> +
> + return 0;
> +}
> +
> +static int panel_claa101_get_modes(struct display_entity *entity,
> + const struct videomode **modes)
> +{
> + /* TODO get modes from EDID? */
Why not move the "nvidia,ddc" from encoder's DT to panel's DT? In that
case, you can get EDID here. I know drm has some helpers to fetch EDID
but I recall there are some other functions which has no drm
dependencies which may be suitable for you.
> + return 0;
> +}
[...]
> +
> +static int __exit panel_claa101_remove(struct platform_device *pdev)
> +{
> + struct panel_claa101 *panel = platform_get_drvdata(pdev);
> +
> + display_entity_unregister(&panel->entity);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_OF
We don't need this kind of "ifdef" in upstream kernel.
> +static struct of_device_id panel_claa101_of_match[] = {
> + { .compatible = "chunghwa,claa101wa01a", },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, pwm_backlight_of_match);
What does this mean? Why we need this?
> +#else
> +#endif
> +
> +static const struct dev_pm_ops panel_claa101_dev_pm_ops = {
> +};
> +
> +static struct platform_driver panel_claa101_driver = {
> + .probe = panel_claa101_probe,
> + .remove = panel_claa101_remove,
> + .driver = {
> + .name = "panel_claa101wa01a",
> + .owner = THIS_MODULE,
> +#ifdef CONFIG_PM
> + .pm = &panel_claa101_dev_pm_ops,
If you haven't implemented this in this patch set, I suggest removing this.
> +#endif
> +#ifdef CONFIG_OF
> + .of_match_table = of_match_ptr(panel_claa101_of_match),
> +#endif
> + },
> +};
> +
> +module_platform_driver(panel_claa101_driver);
> +
> +MODULE_AUTHOR("Alexandre Courbot <acourbot@nvidia.com>");
> +MODULE_DESCRIPTION("Chunghwa CLAA101WA01A Display Panel");
> +MODULE_LICENSE("GPL");
>
^ permalink raw reply
* Re: [RFC 3/4] drm: tegra: use the Common Display Framework
From: Thierry Reding @ 2013-01-30 7:24 UTC (permalink / raw)
To: Alex Courbot
Cc: Mark Zhang, Laurent Pinchart, Stephen Warren, Mark Zhang,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
gnurou-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org
In-Reply-To: <5108C55C.30104-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
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On Wed, Jan 30, 2013 at 04:01:48PM +0900, Alex Courbot wrote:
> On 01/30/2013 03:50 PM, Mark Zhang wrote:
> >>@@ -147,6 +148,9 @@ struct tegra_output {
> >>
> >> struct drm_encoder encoder;
> >> struct drm_connector connector;
> >>+ struct display_entity this;
> >>+ struct display_entity *output;
> >
> >Could you pick up a somewhat meaningful name? You know, there are too
> >many variables with name "drm/connector/output/encoder"... :)
>
> Well, it's supposed to be abstract. From the CDF point of view it
> could be anything besides a panel. I know this makes it an output of
> an output, but I can't think of anything better right now.
How about renaming "this" to stream to match with what the output is in
CDF speak. And the output's output is the panel, right? Why not just
call it that? Even if it isn't directly connected to a panel entity but
has indeed a whole pipeline in between, for tegra-drm it is still a
panel.
Thierry
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^ permalink raw reply
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