* Re: [RFC] Add co-maintainer for fbdev
From: Jingoo Han @ 2013-05-27 8:19 UTC (permalink / raw)
To: 'Tomi Valkeinen',
'Jean-Christophe PLAGNIOL-VILLARD'
Cc: 'Florian Tobias Schandinat', 'Arnd Bergmann',
'Olof Johansson', linux-fbdev, 'Linus Torvalds',
linux-kernel, 'Andrew Morton'
In-Reply-To: <51A31013.9010701@ti.com>
On Monday, May 27, 2013 4:50 PM, Jean-Christophe PLAGNIOL-VILLARD wrote:
>
> Hi Jean-Christophe,
>
> >>> On Fri, May 24, 2013 at 8:38 AM, Jean-Christophe PLAGNIOL-VILLARD
> >>> <plagnioj@jcrosoft.com> wrote:
> >>>> Hi Florian,
> >>>>
> >>>> As you seems very busy I'd like to propose the help you to handle the
> >>>> fbdev subsystem to easier the rich of the fbdev patch to Linus
> >>>>
> >>>> As I'm working on fbdev on at91 and others and already Co-Maintain the
> >>>> at91 mach on ARM
> >>>>
> >>>> And if you are not willing to continue I could take over
>
> I've been collecting fbdev patches for the latest merge windows, so that
> Linus doesn't get tons of small separate pull requests. But I haven't
> been very proactive with that, and I don't think I have time to really
> maintain fbdev.
Hi Tomi,
I really thank you for your previous efforts.
Actually, I thought that you're a good fit for fbdev.
>
> So I'd also welcome somebody stepping up and taking taking on the
> maintainership of fbdev.
Hi Jean-Christophe PLAGNIOL-VILLARD,
I agree with Tomi's opinion.
If you take the maintainership of fbdev, it will be very helpful.
Best regards,
Jingoo Han
>
> Tomi
>
> Ps. I already have a few patches for 3.10 and for 3.11. I'll send them
> to you.
>
^ permalink raw reply
* [PATCH] console/dummy: Move screen size selection from CPP to Kconfig
From: Geert Uytterhoeven @ 2013-05-27 8:36 UTC (permalink / raw)
To: linux-arm-kernel
PA-RISC already handled the dummy console screen size selection in Kconfig,
so generalize this to other platforms.
ARM keeps on using screen_info, which is filled in by platform-specific
code, or from ATAGS.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
drivers/video/console/Kconfig | 16 ++++++++++------
drivers/video/console/dummycon.c | 5 +----
2 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/drivers/video/console/Kconfig b/drivers/video/console/Kconfig
index 8af6ad3..7bfe7e1 100644
--- a/drivers/video/console/Kconfig
+++ b/drivers/video/console/Kconfig
@@ -76,18 +76,22 @@ config DUMMY_CONSOLE
config DUMMY_CONSOLE_COLUMNS
int "Initial number of console screen columns"
- depends on PARISC && DUMMY_CONSOLE
- default "160"
+ depends on DUMMY_CONSOLE && !ARM
+ default 160 if PARISC
+ default 80
help
- The default value is 160, which should fit a 1280x1024 monitor.
+ On PA-RISC, the default value is 160, which should fit a 1280x1024
+ monitor.
Select 80 if you use a 640x480 resolution by default.
config DUMMY_CONSOLE_ROWS
int "Initial number of console screen rows"
- depends on PARISC && DUMMY_CONSOLE
- default "64"
+ depends on DUMMY_CONSOLE && !ARM
+ default 64 if PARISC
+ default 25
help
- The default value is 64, which should fit a 1280x1024 monitor.
+ On PA-RISC, the default value is 64, which should fit a 1280x1024
+ monitor.
Select 25 if you use a 640x480 resolution by default.
config FRAMEBUFFER_CONSOLE
diff --git a/drivers/video/console/dummycon.c b/drivers/video/console/dummycon.c
index b63860f..6b1a5d1 100644
--- a/drivers/video/console/dummycon.c
+++ b/drivers/video/console/dummycon.c
@@ -20,13 +20,10 @@
#if defined(__arm__)
#define DUMMY_COLUMNS screen_info.orig_video_cols
#define DUMMY_ROWS screen_info.orig_video_lines
-#elif defined(__hppa__)
+#else
/* set by Kconfig. Use 80x25 for 640x480 and 160x64 for 1280x1024 */
#define DUMMY_COLUMNS CONFIG_DUMMY_CONSOLE_COLUMNS
#define DUMMY_ROWS CONFIG_DUMMY_CONSOLE_ROWS
-#else
-#define DUMMY_COLUMNS 80
-#define DUMMY_ROWS 25
#endif
static const char *dummycon_startup(void)
--
1.7.0.4
^ permalink raw reply related
* Re: [PATCH v6] video: imxfb: Add DT support
From: Sascha Hauer @ 2013-05-27 9:06 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <1369564538-21835-1-git-send-email-mpa@pengutronix.de>
On Sun, May 26, 2013 at 12:35:38PM +0200, Markus Pargmann wrote:
> Add devicetree support for imx framebuffer driver. It uses the generic
> display bindings and helper functions.
>
> Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
> Cc: Fabio Estevam <festevam@gmail.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Sascha
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply
* RE: Introduce a new helper framework for buffer synchronization
From: Inki Dae @ 2013-05-27 10:38 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <51909DB4.2060208@canonical.com>
Hi all,
I have been removed previous branch and added new one with more cleanup.
This time, the fence helper doesn't include user side interfaces and cache
operation relevant codes anymore because not only we are not sure that
coupling those two things, synchronizing caches and buffer access between
CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side is a
good idea yet but also existing codes for user side have problems with badly
behaved or crashing userspace. So this could be more discussed later.
The below is a new branch,
https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/?h=dma-f
ence-helper
And fence helper codes,
https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?
h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
And example codes for device driver,
https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?
h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
I think the time is not yet ripe for RFC posting: maybe existing dma fence
and reservation need more review and addition work. So I'd glad for somebody
giving other opinions and advices in advance before RFC posting.
Thanks,
Inki Dae
^ permalink raw reply
* [PATCH] video: display_timing: make parameter const
From: Lucas Stach @ 2013-05-27 12:33 UTC (permalink / raw)
To: dri-devel; +Cc: Dave Airlie, linux-fbdev, kernel, Florian Tobias Schandinat
From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
As the device_node pointer is not changed in of_get_display_timing and
parse_timing_property it can be a const pointer.
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
drivers/video/of_display_timing.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/video/of_display_timing.c b/drivers/video/of_display_timing.c
index 56009bc..85c1a41 100644
--- a/drivers/video/of_display_timing.c
+++ b/drivers/video/of_display_timing.c
@@ -23,7 +23,7 @@
* Every display_timing can be specified with either just the typical value or
* a range consisting of min/typ/max. This function helps handling this
**/
-static int parse_timing_property(struct device_node *np, const char *name,
+static int parse_timing_property(const struct device_node *np, const char *name,
struct timing_entry *result)
{
struct property *prop;
@@ -56,7 +56,8 @@ static int parse_timing_property(struct device_node *np, const char *name,
* of_get_display_timing - parse display_timing entry from device_node
* @np: device_node with the properties
**/
-static struct display_timing *of_get_display_timing(struct device_node *np)
+static struct display_timing *of_get_display_timing(const struct device_node
+ *np)
{
struct display_timing *dt;
u32 val = 0;
--
1.7.10.4
^ permalink raw reply related
* [PATCH 1/3] video: display_timing: add doubleclk flag
From: Lucas Stach @ 2013-05-27 12:33 UTC (permalink / raw)
To: dri-devel; +Cc: Dave Airlie, linux-fbdev, kernel, Florian Tobias Schandinat
From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
include/video/display_timing.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/video/display_timing.h b/include/video/display_timing.h
index 5d0259b..28d9d0d 100644
--- a/include/video/display_timing.h
+++ b/include/video/display_timing.h
@@ -27,6 +27,7 @@ enum display_flags {
DISPLAY_FLAGS_PIXDATA_NEGEDGE = BIT(7),
DISPLAY_FLAGS_INTERLACED = BIT(8),
DISPLAY_FLAGS_DOUBLESCAN = BIT(9),
+ DISPLAY_FLAGS_DOUBLECLK = BIT(10),
};
/*
--
1.7.10.4
^ permalink raw reply related
* [PATCH 2/3] video: of: display_timing: add doubleclk flag
From: Lucas Stach @ 2013-05-27 12:33 UTC (permalink / raw)
To: dri-devel; +Cc: Dave Airlie, linux-fbdev, kernel, Florian Tobias Schandinat
In-Reply-To: <1369658015-11743-1-git-send-email-l.stach@pengutronix.de>
From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
Documentation/devicetree/bindings/video/display-timing.txt | 1 +
drivers/video/of_display_timing.c | 2 ++
2 files changed, 3 insertions(+)
diff --git a/Documentation/devicetree/bindings/video/display-timing.txt b/Documentation/devicetree/bindings/video/display-timing.txt
index 1500385..e1d4a0b 100644
--- a/Documentation/devicetree/bindings/video/display-timing.txt
+++ b/Documentation/devicetree/bindings/video/display-timing.txt
@@ -34,6 +34,7 @@ optional properties:
- ignored = ignored
- interlaced (bool): boolean to enable interlaced mode
- doublescan (bool): boolean to enable doublescan mode
+ - doubleclk (bool): boolean to enable doubleclock mode
All the optional properties that are not bool follow the following logic:
<1>: high active
diff --git a/drivers/video/of_display_timing.c b/drivers/video/of_display_timing.c
index 85c1a41..2894e03 100644
--- a/drivers/video/of_display_timing.c
+++ b/drivers/video/of_display_timing.c
@@ -98,6 +98,8 @@ static struct display_timing *of_get_display_timing(const struct device_node
dt->flags |= DISPLAY_FLAGS_INTERLACED;
if (of_property_read_bool(np, "doublescan"))
dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
+ if (of_property_read_bool(np, "doubleclk"))
+ dt->flags |= DISPLAY_FLAGS_DOUBLECLK;
if (ret) {
pr_err("%s: error reading timing properties\n",
--
1.7.10.4
^ permalink raw reply related
* [PATCH 3/3] drm_modes: videomode: add doubleclk flag
From: Lucas Stach @ 2013-05-27 12:33 UTC (permalink / raw)
To: dri-devel; +Cc: Dave Airlie, linux-fbdev, kernel, Florian Tobias Schandinat
In-Reply-To: <1369658015-11743-1-git-send-email-l.stach@pengutronix.de>
From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
---
drivers/gpu/drm/drm_modes.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index faa79df..875031d 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -535,6 +535,8 @@ int drm_display_mode_from_videomode(const struct videomode *vm,
dmode->flags |= DRM_MODE_FLAG_INTERLACE;
if (vm->flags & DISPLAY_FLAGS_DOUBLESCAN)
dmode->flags |= DRM_MODE_FLAG_DBLSCAN;
+ if (vm->flags & DISPLAY_FLAGS_DOUBLECLK)
+ dmode->flags |= DRM_MODE_FLAG_DBLCLK;
drm_mode_set_name(dmode);
return 0;
--
1.7.10.4
^ permalink raw reply related
* Re: [RFC] Add co-maintainer for fbdev
From: Jean-Christophe PLAGNIOL-VILLARD @ 2013-05-27 12:42 UTC (permalink / raw)
To: Tomi Valkeinen
Cc: Florian Tobias Schandinat, Arnd Bergmann, Olof Johansson,
linux-fbdev, Linus Torvalds, linux-kernel@vger.kernel.org,
Andrew Morton
In-Reply-To: <51A31013.9010701@ti.com>
On 10:49 Mon 27 May , Tomi Valkeinen wrote:
> Hi Jean-Christophe,
>
> >>> On Fri, May 24, 2013 at 8:38 AM, Jean-Christophe PLAGNIOL-VILLARD
> >>> <plagnioj@jcrosoft.com> wrote:
> >>>> Hi Florian,
> >>>>
> >>>> As you seems very busy I'd like to propose the help you to handle the
> >>>> fbdev subsystem to easier the rich of the fbdev patch to Linus
> >>>>
> >>>> As I'm working on fbdev on at91 and others and already Co-Maintain the
> >>>> at91 mach on ARM
> >>>>
> >>>> And if you are not willing to continue I could take over
>
> I've been collecting fbdev patches for the latest merge windows, so that
> Linus doesn't get tons of small separate pull requests. But I haven't
> been very proactive with that, and I don't think I have time to really
> maintain fbdev.
>
> So I'd also welcome somebody stepping up and taking taking on the
> maintainership of fbdev.
>
> Tomi
>
> Ps. I already have a few patches for 3.10 and for 3.11. I'll send them
> to you.
Just send a pull request
for the 3.10 ASAP the 3.11 later I've ask a tree on kernel.org I'll then
request an inclusion on linux-next
Best Regards,
J.
>
>
^ permalink raw reply
* Re: [RFC] Add co-maintainer for fbdev
From: Jean-Christophe PLAGNIOL-VILLARD @ 2013-05-27 14:38 UTC (permalink / raw)
To: Florian Tobias Schandinat
Cc: Arnd Bergmann, Olof Johansson, linux-fbdev, Linus Torvalds,
linux-kernel@vger.kernel.org, Tomi Valkeinen, Andrew Morton
In-Reply-To: <51A29DB9.7030505@gmx.de>
On 23:41 Sun 26 May , Florian Tobias Schandinat wrote:
> Hi Jean-Christophe,
>
> On 05/24/2013 06:56 PM, Arnd Bergmann wrote:
> > On Friday 24 May 2013, Olof Johansson wrote:
> >> [+akpm]
> >
> > [+florian]
>
> Thanks for CC'ing me. Lately I got dropped frequently from the
> mailinglist (after 1 or 2 days). Guess I should try subscribing via my
> own mail server.
>
> >> On Fri, May 24, 2013 at 8:38 AM, Jean-Christophe PLAGNIOL-VILLARD
> >> <plagnioj@jcrosoft.com> wrote:
> >>> Hi Florian,
> >>>
> >>> As you seems very busy I'd like to propose the help you to handle the
> >>> fbdev subsystem to easier the rich of the fbdev patch to Linus
> >>>
> >>> As I'm working on fbdev on at91 and others and already Co-Maintain the
> >>> at91 mach on ARM
> >>>
> >>> And if you are not willing to continue I could take over
>
> Yeah, it would be great if you could help, at the moment I get barely
> any sleep, let alone that I could keep up with the majority of mail I
> get. I'll let you decide whether you want to be sole maintainer or not.
I'd like to have feed back from others on this
> I still have interest in the subsystem, but it looks like VIA won't
> provide any information for their new VX11 chipset IGP for any open
> source driver and I'm still looking for a small, quiet mobile device as
> a replacement for my precious netbook that broke down last autumn to
> allow me working when I'm not at home.
I personnaly use a MacBook Air 11" with a powerpack to extend it to 15h of
battery
>
> >> Andrew has been fallback fbdev maintainer for a while, we have the
> >> option of formalizing that as well. Adding him on cc so he sees this.
>
> At this point I'd like to thank all people who have helped out so far,
> especially Tomi and Andrew.
>
>
> Best regards,
>
> Florian Tobias Schandinat
^ permalink raw reply
* Re: [PATCH 1/3] video: display_timing: add doubleclk flag
From: Jean-Christophe PLAGNIOL-VILLARD @ 2013-05-27 14:43 UTC (permalink / raw)
To: Lucas Stach
Cc: Dave Airlie, linux-fbdev, kernel, dri-devel,
Florian Tobias Schandinat
In-Reply-To: <1369658015-11743-1-git-send-email-l.stach@pengutronix.de>
On 14:33 Mon 27 May , Lucas Stach wrote:
> From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
>
> Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
If you want to take it via dri I'm fine otherwise via fbdev
Best Regards,
J.
> ---
> include/video/display_timing.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/video/display_timing.h b/include/video/display_timing.h
> index 5d0259b..28d9d0d 100644
> --- a/include/video/display_timing.h
> +++ b/include/video/display_timing.h
> @@ -27,6 +27,7 @@ enum display_flags {
> DISPLAY_FLAGS_PIXDATA_NEGEDGE = BIT(7),
> DISPLAY_FLAGS_INTERLACED = BIT(8),
> DISPLAY_FLAGS_DOUBLESCAN = BIT(9),
> + DISPLAY_FLAGS_DOUBLECLK = BIT(10),
> };
>
> /*
> --
> 1.7.10.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply
* Re: [PATCH] video: mxsfb: Let device core handle pinctrl
From: Jean-Christophe PLAGNIOL-VILLARD @ 2013-05-27 14:44 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <1369619294-10362-1-git-send-email-festevam@gmail.com>
On 22:48 Sun 26 May , Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@freescale.com>
>
> Since commit ab78029 (drivers/pinctrl: grab default handles from device core)
> we can rely on device core for handling pinctrl, so remove
> devm_pinctrl_get_select_default() from the driver.
Linus we should do a pass on the kernel to clean this
Best Regards,
J.
>
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
> drivers/video/mxsfb.c | 8 --------
> 1 file changed, 8 deletions(-)
>
> diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
> index 21223d4..9d6a286 100644
> --- a/drivers/video/mxsfb.c
> +++ b/drivers/video/mxsfb.c
> @@ -46,7 +46,6 @@
> #include <linux/clk.h>
> #include <linux/dma-mapping.h>
> #include <linux/io.h>
> -#include <linux/pinctrl/consumer.h>
> #include <linux/fb.h>
> #include <linux/regulator/consumer.h>
> #include <video/of_display_timing.h>
> @@ -877,7 +876,6 @@ static int mxsfb_probe(struct platform_device *pdev)
> struct mxsfb_info *host;
> struct fb_info *fb_info;
> struct fb_modelist *modelist;
> - struct pinctrl *pinctrl;
> int ret;
>
> if (of_id)
> @@ -909,12 +907,6 @@ static int mxsfb_probe(struct platform_device *pdev)
>
> host->devdata = &mxsfb_devdata[pdev->id_entry->driver_data];
>
> - pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
> - if (IS_ERR(pinctrl)) {
> - ret = PTR_ERR(pinctrl);
> - goto fb_release;
> - }
> -
> host->clk = devm_clk_get(&host->pdev->dev, NULL);
> if (IS_ERR(host->clk)) {
> ret = PTR_ERR(host->clk);
> --
> 1.8.1.2
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply
* Re: Introduce a new helper framework for buffer synchronization
From: Maarten Lankhorst @ 2013-05-27 15:23 UTC (permalink / raw)
To: Inki Dae
Cc: 'Daniel Vetter', 'Rob Clark',
'linux-fbdev', 'YoungJun Cho',
'Kyungmin Park', 'myungjoo.ham',
'DRI mailing list', linux-arm-kernel, linux-media
In-Reply-To: <014501ce5ac6$511a8500$f34f8f00$%dae@samsung.com>
Hey,
Op 27-05-13 12:38, Inki Dae schreef:
> Hi all,
>
> I have been removed previous branch and added new one with more cleanup.
> This time, the fence helper doesn't include user side interfaces and cache
> operation relevant codes anymore because not only we are not sure that
> coupling those two things, synchronizing caches and buffer access between
> CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side is a
> good idea yet but also existing codes for user side have problems with badly
> behaved or crashing userspace. So this could be more discussed later.
>
> The below is a new branch,
>
> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/?h=dma-f
> ence-helper
>
> And fence helper codes,
>
> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?
> h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
>
> And example codes for device driver,
>
> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?
> h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
>
> I think the time is not yet ripe for RFC posting: maybe existing dma fence
> and reservation need more review and addition work. So I'd glad for somebody
> giving other opinions and advices in advance before RFC posting.
>
NAK.
For examples for how to handle locking properly, see Documentation/ww-mutex-design.txt in my recent tree.
I could list what I believe is wrong with your implementation, but real problem is that the approach you're taking is wrong.
~Maarten
^ permalink raw reply
* Re: Introduce a new helper framework for buffer synchronization
From: Rob Clark @ 2013-05-27 15:47 UTC (permalink / raw)
To: Inki Dae
Cc: Maarten Lankhorst, Daniel Vetter, linux-fbdev, YoungJun Cho,
Kyungmin Park, myungjoo.ham, DRI mailing list, linux-arm-kernel,
linux-media
In-Reply-To: <014501ce5ac6$511a8500$f34f8f00$%dae@samsung.com>
On Mon, May 27, 2013 at 6:38 AM, Inki Dae <inki.dae@samsung.com> wrote:
> Hi all,
>
> I have been removed previous branch and added new one with more cleanup.
> This time, the fence helper doesn't include user side interfaces and cache
> operation relevant codes anymore because not only we are not sure that
> coupling those two things, synchronizing caches and buffer access between
> CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side is a
> good idea yet but also existing codes for user side have problems with badly
> behaved or crashing userspace. So this could be more discussed later.
>
> The below is a new branch,
>
> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/?h=dma-f
> ence-helper
>
> And fence helper codes,
>
> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?
> h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
>
> And example codes for device driver,
>
> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?
> h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
>
> I think the time is not yet ripe for RFC posting: maybe existing dma fence
> and reservation need more review and addition work. So I'd glad for somebody
> giving other opinions and advices in advance before RFC posting.
thoughts from a *really* quick, pre-coffee, first look:
* any sort of helper to simplify single-buffer sort of use-cases (v4l)
probably wouldn't want to bake in assumption that seqno_fence is used.
* I guess g2d is probably not actually a simple use case, since I
expect you can submit blits involving multiple buffers :-P
* otherwise, you probably don't want to depend on dmabuf, which is why
reservation/fence is split out the way it is.. you want to be able to
use a single reservation/fence mechanism within your driver without
having to care about which buffers are exported to dmabuf's and which
are not. Creating a dmabuf for every GEM bo is too heavyweight.
I'm not entirely sure if reservation/fence could/should be made any
simpler for multi-buffer users. Probably the best thing to do is just
get reservation/fence rolled out in a few drivers and see if some
common patterns emerge.
BR,
-R
>
> Thanks,
> Inki Dae
>
^ permalink raw reply
* Re: Introduce a new helper framework for buffer synchronization
From: Daniel Vetter @ 2013-05-27 16:02 UTC (permalink / raw)
To: Rob Clark
Cc: Inki Dae, Maarten Lankhorst, linux-fbdev, YoungJun Cho,
Kyungmin Park, myungjoo.ham, DRI mailing list,
linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org
In-Reply-To: <CAF6AEGvGv539Ktdeg03n783nD+HofDamcJCLX93rzzKGOCV8_Q@mail.gmail.com>
On Mon, May 27, 2013 at 5:47 PM, Rob Clark <robdclark@gmail.com> wrote:
> On Mon, May 27, 2013 at 6:38 AM, Inki Dae <inki.dae@samsung.com> wrote:
>> Hi all,
>>
>> I have been removed previous branch and added new one with more cleanup.
>> This time, the fence helper doesn't include user side interfaces and cache
>> operation relevant codes anymore because not only we are not sure that
>> coupling those two things, synchronizing caches and buffer access between
>> CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side is a
>> good idea yet but also existing codes for user side have problems with badly
>> behaved or crashing userspace. So this could be more discussed later.
>>
>> The below is a new branch,
>>
>> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/?h=dma-f
>> ence-helper
>>
>> And fence helper codes,
>>
>> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?
>> h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
>>
>> And example codes for device driver,
>>
>> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-exynos.git/commit/?
>> h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
>>
>> I think the time is not yet ripe for RFC posting: maybe existing dma fence
>> and reservation need more review and addition work. So I'd glad for somebody
>> giving other opinions and advices in advance before RFC posting.
>
> thoughts from a *really* quick, pre-coffee, first look:
> * any sort of helper to simplify single-buffer sort of use-cases (v4l)
> probably wouldn't want to bake in assumption that seqno_fence is used.
Yeah, which is why Maarten&I discussed ideas already for what needs to
be improved in the current dma-buf interface code to make this Just
Work. At least as long as a driver doesn't want to add new fences,
which would be especially useful for all kinds of gpu access.
> * I guess g2d is probably not actually a simple use case, since I
> expect you can submit blits involving multiple buffers :-P
Yeah, on a quick read the current fence helper code seems to be a bit
limited in scope.
> * otherwise, you probably don't want to depend on dmabuf, which is why
> reservation/fence is split out the way it is.. you want to be able to
> use a single reservation/fence mechanism within your driver without
> having to care about which buffers are exported to dmabuf's and which
> are not. Creating a dmabuf for every GEM bo is too heavyweight.
That's pretty much the reason that reservations are free-standing from
dma_bufs. The idea is to embed them into the gem/ttm/v4l buffer
object. Maarten also has some helpers to keep track of multi-buffer
ww_mutex locking and fence attaching in his reservation helpers, but I
think we should wait with those until we have drivers using them.
For now I think the priority should be to get the basic stuff in and
ttm as the first user established. Then we can go nuts later on.
> I'm not entirely sure if reservation/fence could/should be made any
> simpler for multi-buffer users. Probably the best thing to do is just
> get reservation/fence rolled out in a few drivers and see if some
> common patterns emerge.
I think we can make the 1 buffer per dma op (i.e. 1:1
dma_buf->reservation : fence mapping) work fairly simple in dma_buf
with maybe a dma_buf_attachment_start_dma/end_dma helpers. But there's
also still the open that currently there's no way to flush cpu caches
for dma access without unmapping the attachement (or resorting to
trick which might not work), so we have a few gaping holes in the
interface already anyway.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
^ permalink raw reply
* Re: [PATCH v2] video: simplefb: add mode parsing function
From: David Herrmann @ 2013-05-27 18:22 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <1369626821-28494-1-git-send-email-acourbot@nvidia.com>
Hi
On Mon, May 27, 2013 at 5:53 AM, Alexandre Courbot <acourbot@nvidia.com> wrote:
> The naming scheme of simplefb's mode is precise enough to allow building
> the mode structure from it instead of using a static list of modes. This
> patch introduces a function that does this. In case exotic modes that
> cannot be represented from their name alone are needed, the static list
> of modes is still available as a backup.
>
> It also changes the order in which colors are declared from MSB first to
> the more standard LSB first.
>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
> Changes from v1:
> - amended documentation following Stephen's suggestion
> - allow parsing of bitfields larger than 9 bits
> - made it clear that the parsing order of bits is changed with respect
> to the original patch
>
> Andrew, since this patch introduces a (small) change in the DT bindings,
> could we try to merge it during the -rc cycle so we don't have to come
> with a more complex solution in the future?
>
> .../bindings/video/simple-framebuffer.txt | 12 +++-
> drivers/video/simplefb.c | 72 +++++++++++++++++++++-
> 2 files changed, 80 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt
> index 3ea4605..18d03e2 100644
> --- a/Documentation/devicetree/bindings/video/simple-framebuffer.txt
> +++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt
> @@ -10,8 +10,16 @@ Required properties:
> - width: The width of the framebuffer in pixels.
> - height: The height of the framebuffer in pixels.
> - stride: The number of bytes in each line of the framebuffer.
> -- format: The format of the framebuffer surface. Valid values are:
> - - r5g6b5 (16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b).
> +- format: The format of the framebuffer surface. Described as a sequence of
> + channel/num-bits pairs, where each pair describes how many bits are used
> + by a given color channel. Value channels are "r" (red), "g" (green),
> + "b" (blue), "a" (alpha) and "x" (unused). Channels are listed in bit
> + order, starting from the LSB. For instance, a format named "r5g6b5"
> + describes a 16-bit format where red is encoded in the 5 less significant
> + bits, green in the 6 following ones, and blue in the 5 last:
> + BBBBBGGG GGGRRRRR
> + ^ ^
> + MSB LSB
Is there a specific reason why we need arbitrary RGB formats? I have a
KMS/DRM driver based on dvbe that can provide the exact same
functionality as this fbdev driver (including an fbdev
backwards-compat layer). However, DRM does not allow arbitrary formats
but rather provides a huge list of supported formats.
If we apply this patch it will get very hard to support this with a
KMS driver. So any reason why we cannot use the DRM FOURCC constants
instead?
The dvbe proposal is available here: (also see the two following patches)
http://lkml.indiana.edu/hypermail/linux/kernel/1302.2/00274.html
it provides a simple DRM driver that uses VESA / VBE. I am currently
trying to rework it to "SimpleDRM" which can support arbitrary
firmware framebuffers.
Cheers
David
> Example:
>
> diff --git a/drivers/video/simplefb.c b/drivers/video/simplefb.c
> index e2e9e3e..1430752 100644
> --- a/drivers/video/simplefb.c
> +++ b/drivers/video/simplefb.c
> @@ -21,6 +21,7 @@
> */
>
> #include <linux/errno.h>
> +#include <linux/ctype.h>
> #include <linux/fb.h>
> #include <linux/io.h>
> #include <linux/module.h>
> @@ -82,8 +83,72 @@ struct simplefb_format {
> struct fb_bitfield transp;
> };
>
> +static struct simplefb_format *simplefb_parse_format(struct device *dev,
> + const char *str)
> +{
> + struct simplefb_format *format;
> + unsigned int offset = 0;
> + unsigned int i = 0;
> +
> + format = devm_kzalloc(dev, sizeof(*format), GFP_KERNEL);
> + if (!format)
> + return ERR_PTR(-ENOMEM);
> +
> + while (str[i] != 0) {
> + struct fb_bitfield *field = NULL;
> + int length = 0;
> +
> + switch (str[i++]) {
> + case 'r':
> + case 'R':
> + field = &format->red;
> + break;
> + case 'g':
> + case 'G':
> + field = &format->green;
> + break;
> + case 'b':
> + case 'B':
> + field = &format->blue;
> + break;
> + case 'a':
> + case 'A':
> + field = &format->transp;
> + break;
> + case 'x':
> + case 'X':
> + break;
> + default:
> + goto error;
> + }
> +
> + if (!isdigit(str[i]))
> + goto error;
> +
> + while (isdigit(str[i])) {
> + length = length * 10 + (str[i++] - '0');
> + }
> +
> + if (field) {
> + field->offset = offset;
> + field->length = length;
> + }
> +
> + offset += length;
> + }
> +
> + format->bits_per_pixel = (offset + 7) & ~0x7;
> + format->name = str;
> + return format;
> +
> +error:
> + dev_err(dev, "Invalid format string\n");
> + return ERR_PTR(-EINVAL);
> +}
> +
> +/* if you use exotic modes that simplefb_parse_format cannot decode, you can
> + specify them here. */
> static struct simplefb_format simplefb_formats[] = {
> - { "r5g6b5", 16, {11, 5}, {5, 6}, {0, 5}, {0, 0} },
> };
>
> struct simplefb_params {
> @@ -131,7 +196,10 @@ static int simplefb_parse_dt(struct platform_device *pdev,
> params->format = &simplefb_formats[i];
> break;
> }
> - if (!params->format) {
> + if (!params->format)
> + params->format = simplefb_parse_format(&pdev->dev, format);
> +
> + if (IS_ERR(params->format)) {
> dev_err(&pdev->dev, "Invalid format value\n");
> return -EINVAL;
> }
> --
> 1.8.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply
* Re: [PATCH v2] video: simplefb: add mode parsing function
From: Alexandre Courbot @ 2013-05-28 2:31 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <CANq1E4Qa6g-zrA6o_u3w6mpVcUk8-ZPPR+edu6EXgpk-kGQULQ@mail.gmail.com>
Hi David,
On Tue, May 28, 2013 at 3:22 AM, David Herrmann <dh.herrmann@gmail.com> wrote:
> If we apply this patch it will get very hard to support this with a
> KMS driver. So any reason why we cannot use the DRM FOURCC constants
> instead?
I don't see any. Maybe Stephen can confirm.
> The dvbe proposal is available here: (also see the two following patches)
> http://lkml.indiana.edu/hypermail/linux/kernel/1302.2/00274.html
>
> it provides a simple DRM driver that uses VESA / VBE. I am currently
> trying to rework it to "SimpleDRM" which can support arbitrary
> firmware framebuffers.
Ok. I am personally fine with using FOURCC codes for describing video
modes. Maybe we can just drop this patch if it gets in your way.
Alex.
^ permalink raw reply
* RE: Introduce a new helper framework for buffer synchronization
From: Inki Dae @ 2013-05-28 2:49 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <51909DB4.2060208@canonical.com>
> -----Original Message-----
> From: Maarten Lankhorst [mailto:maarten.lankhorst@canonical.com]
> Sent: Tuesday, May 28, 2013 12:23 AM
> To: Inki Dae
> Cc: 'Daniel Vetter'; 'Rob Clark'; 'linux-fbdev'; 'YoungJun Cho'; 'Kyungmin
> Park'; 'myungjoo.ham'; 'DRI mailing list'; linux-arm-
> kernel@lists.infradead.org; linux-media@vger.kernel.org
> Subject: Re: Introduce a new helper framework for buffer synchronization
>
> Hey,
>
> Op 27-05-13 12:38, Inki Dae schreef:
> > Hi all,
> >
> > I have been removed previous branch and added new one with more cleanup.
> > This time, the fence helper doesn't include user side interfaces and
> cache
> > operation relevant codes anymore because not only we are not sure that
> > coupling those two things, synchronizing caches and buffer access
> between
> > CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side is
> a
> > good idea yet but also existing codes for user side have problems with
> badly
> > behaved or crashing userspace. So this could be more discussed later.
> >
> > The below is a new branch,
> >
> > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/?h=dma-f
> > ence-helper
> >
> > And fence helper codes,
> >
> > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/commit/?
> > h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
> >
> > And example codes for device driver,
> >
> > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/commit/?
> > h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
> >
> > I think the time is not yet ripe for RFC posting: maybe existing dma
> fence
> > and reservation need more review and addition work. So I'd glad for
> somebody
> > giving other opinions and advices in advance before RFC posting.
> >
> NAK.
>
> For examples for how to handle locking properly, see Documentation/ww-
> mutex-design.txt in my recent tree.
> I could list what I believe is wrong with your implementation, but real
> problem is that the approach you're taking is wrong.
I just removed ticket stubs to show my approach you guys as simple as
possible, and I just wanted to show that we could use buffer synchronization
mechanism without ticket stubs.
Question, WW-Mutexes could be used for all devices? I guess this has
dependence on x86 gpu: gpu has VRAM and it means different memory domain.
And could you tell my why shared fence should have only eight objects? I
think we could need more than eight objects for read access. Anyway I think
I don't surely understand yet so there might be my missing point.
Thanks,
Inki Dae
>
> ~Maarten
^ permalink raw reply
* RE: Introduce a new helper framework for buffer synchronization
From: Inki Dae @ 2013-05-28 3:56 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <51909DB4.2060208@canonical.com>
> -----Original Message-----
> From: linux-fbdev-owner@vger.kernel.org [mailto:linux-fbdev-
> owner@vger.kernel.org] On Behalf Of Rob Clark
> Sent: Tuesday, May 28, 2013 12:48 AM
> To: Inki Dae
> Cc: Maarten Lankhorst; Daniel Vetter; linux-fbdev; YoungJun Cho; Kyungmin
> Park; myungjoo.ham; DRI mailing list;
linux-arm-kernel@lists.infradead.org;
> linux-media@vger.kernel.org
> Subject: Re: Introduce a new helper framework for buffer synchronization
>
> On Mon, May 27, 2013 at 6:38 AM, Inki Dae <inki.dae@samsung.com> wrote:
> > Hi all,
> >
> > I have been removed previous branch and added new one with more cleanup.
> > This time, the fence helper doesn't include user side interfaces and
> cache
> > operation relevant codes anymore because not only we are not sure that
> > coupling those two things, synchronizing caches and buffer access
> between
> > CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side is
> a
> > good idea yet but also existing codes for user side have problems with
> badly
> > behaved or crashing userspace. So this could be more discussed later.
> >
> > The below is a new branch,
> >
> > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/?h=dma-f
> > ence-helper
> >
> > And fence helper codes,
> >
> > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/commit/?
> > h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
> >
> > And example codes for device driver,
> >
> > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/commit/?
> > h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
> >
> > I think the time is not yet ripe for RFC posting: maybe existing dma
> fence
> > and reservation need more review and addition work. So I'd glad for
> somebody
> > giving other opinions and advices in advance before RFC posting.
>
> thoughts from a *really* quick, pre-coffee, first look:
> * any sort of helper to simplify single-buffer sort of use-cases (v4l)
> probably wouldn't want to bake in assumption that seqno_fence is used.
> * I guess g2d is probably not actually a simple use case, since I
> expect you can submit blits involving multiple buffers :-P
I don't think so. One and more buffers can be used: seqno_fence also has
only one buffer. Actually, we have already applied this approach to most
devices; multimedia, gpu and display controller. And this approach shows
more performance; reduced power consumption against traditional way. And g2d
example is just to show you how to apply my approach to device driver.
> * otherwise, you probably don't want to depend on dmabuf, which is why
> reservation/fence is split out the way it is.. you want to be able to
> use a single reservation/fence mechanism within your driver without
> having to care about which buffers are exported to dmabuf's and which
> are not. Creating a dmabuf for every GEM bo is too heavyweight.
Right. But I think we should dealt with this separately. Actually, we are
trying to use reservation for gpu pipe line synchronization such as sgx sync
object and this approach is used without dmabuf. In order words, some device
can use only reservation for such pipe line synchronization and at the same
time, fence helper or similar thing with dmabuf for buffer synchronization.
>
> I'm not entirely sure if reservation/fence could/should be made any
> simpler for multi-buffer users. Probably the best thing to do is just
> get reservation/fence rolled out in a few drivers and see if some
> common patterns emerge.
>
> BR,
> -R
>
> >
> > Thanks,
> > Inki Dae
> >
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply
* RE: Introduce a new helper framework for buffer synchronization
From: Inki Dae @ 2013-05-28 4:04 UTC (permalink / raw)
To: linux-fbdev
In-Reply-To: <51909DB4.2060208@canonical.com>
> -----Original Message-----
> From: daniel.vetter@ffwll.ch [mailto:daniel.vetter@ffwll.ch] On Behalf Of
> Daniel Vetter
> Sent: Tuesday, May 28, 2013 1:02 AM
> To: Rob Clark
> Cc: Inki Dae; Maarten Lankhorst; linux-fbdev; YoungJun Cho; Kyungmin Park;
> myungjoo.ham; DRI mailing list; linux-arm-kernel@lists.infradead.org;
> linux-media@vger.kernel.org
> Subject: Re: Introduce a new helper framework for buffer synchronization
>
> On Mon, May 27, 2013 at 5:47 PM, Rob Clark <robdclark@gmail.com> wrote:
> > On Mon, May 27, 2013 at 6:38 AM, Inki Dae <inki.dae@samsung.com> wrote:
> >> Hi all,
> >>
> >> I have been removed previous branch and added new one with more
cleanup.
> >> This time, the fence helper doesn't include user side interfaces and
> cache
> >> operation relevant codes anymore because not only we are not sure that
> >> coupling those two things, synchronizing caches and buffer access
> between
> >> CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side
> is a
> >> good idea yet but also existing codes for user side have problems with
> badly
> >> behaved or crashing userspace. So this could be more discussed later.
> >>
> >> The below is a new branch,
> >>
> >> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/?h=dma-f
> >> ence-helper
> >>
> >> And fence helper codes,
> >>
> >> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/commit/?
> >> h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
> >>
> >> And example codes for device driver,
> >>
> >> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> exynos.git/commit/?
> >> h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
> >>
> >> I think the time is not yet ripe for RFC posting: maybe existing dma
> fence
> >> and reservation need more review and addition work. So I'd glad for
> somebody
> >> giving other opinions and advices in advance before RFC posting.
> >
> > thoughts from a *really* quick, pre-coffee, first look:
> > * any sort of helper to simplify single-buffer sort of use-cases (v4l)
> > probably wouldn't want to bake in assumption that seqno_fence is used.
>
> Yeah, which is why Maarten&I discussed ideas already for what needs to
> be improved in the current dma-buf interface code to make this Just
> Work. At least as long as a driver doesn't want to add new fences,
> which would be especially useful for all kinds of gpu access.
>
> > * I guess g2d is probably not actually a simple use case, since I
> > expect you can submit blits involving multiple buffers :-P
>
> Yeah, on a quick read the current fence helper code seems to be a bit
> limited in scope.
>
> > * otherwise, you probably don't want to depend on dmabuf, which is why
> > reservation/fence is split out the way it is.. you want to be able to
> > use a single reservation/fence mechanism within your driver without
> > having to care about which buffers are exported to dmabuf's and which
> > are not. Creating a dmabuf for every GEM bo is too heavyweight.
>
> That's pretty much the reason that reservations are free-standing from
> dma_bufs. The idea is to embed them into the gem/ttm/v4l buffer
> object. Maarten also has some helpers to keep track of multi-buffer
> ww_mutex locking and fence attaching in his reservation helpers, but I
> think we should wait with those until we have drivers using them.
>
> For now I think the priority should be to get the basic stuff in and
> ttm as the first user established. Then we can go nuts later on.
>
> > I'm not entirely sure if reservation/fence could/should be made any
> > simpler for multi-buffer users. Probably the best thing to do is just
> > get reservation/fence rolled out in a few drivers and see if some
> > common patterns emerge.
>
> I think we can make the 1 buffer per dma op (i.e. 1:1
> dma_buf->reservation : fence mapping) work fairly simple in dma_buf
> with maybe a dma_buf_attachment_start_dma/end_dma helpers. But there's
> also still the open that currently there's no way to flush cpu caches
> for dma access without unmapping the attachement (or resorting to
That was what I tried adding user interfaces to dmabuf: coupling
synchronizing caches and buffer access between CPU and CPU, CPU and DMA, and
DMA and DMA with fences in kernel side. We need something to do between
mapping and unmapping attachment.
> trick which might not work), so we have a few gaping holes in the
> interface already anyway.
> -Daniel
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
^ permalink raw reply
* Re: [PATCH v2] video: simplefb: add mode parsing function
From: Stephen Warren @ 2013-05-28 4:13 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <1369626821-28494-1-git-send-email-acourbot@nvidia.com>
On 05/26/2013 09:53 PM, Alexandre Courbot wrote:
> The naming scheme of simplefb's mode is precise enough to allow building
> the mode structure from it instead of using a static list of modes. This
> patch introduces a function that does this. In case exotic modes that
> cannot be represented from their name alone are needed, the static list
> of modes is still available as a backup.
>
> It also changes the order in which colors are declared from MSB first to
> the more standard LSB first.
>
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
> Changes from v1:
> - amended documentation following Stephen's suggestion
> - allow parsing of bitfields larger than 9 bits
> - made it clear that the parsing order of bits is changed with respect
> to the original patch
>
> Andrew, since this patch introduces a (small) change in the DT bindings,
> could we try to merge it during the -rc cycle so we don't have to come
> with a more complex solution in the future?
So, I think we shouldn't change the DT binding at all now. The original
driver is now merged for 3.10, and I think it's far too late to take
code that implements new features for 3.10. This means that we couldn't
merge this patch until 3.11. However, by then, we shouldn't be changing
the DT binding in incompatible ways. Olof has already published some
U-Boot binaries that use the current binding, and on IRC indicated he'd
prefer not to change the binding because of that.
As such, we should either:
a) Just add new entries into the format array that already exists in the
driver. Given David's response, this might be simplest.
b) Extend the DT binding in a 100% backwards-compatible way, which would
mean defaulting the bit-order to match the existing 1 format, and adding
a new Boolean property to indicate that the format string is specified
in the other order.
^ permalink raw reply
* Re: [PATCH v2] video: simplefb: add mode parsing function
From: Alexandre Courbot @ 2013-05-28 4:57 UTC (permalink / raw)
To: linux-arm-kernel
In-Reply-To: <51A42ED5.2060104@wwwdotorg.org>
On Tue, May 28, 2013 at 1:13 PM, Stephen Warren <swarren@wwwdotorg.org> wrote:
> On 05/26/2013 09:53 PM, Alexandre Courbot wrote:
>> The naming scheme of simplefb's mode is precise enough to allow building
>> the mode structure from it instead of using a static list of modes. This
>> patch introduces a function that does this. In case exotic modes that
>> cannot be represented from their name alone are needed, the static list
>> of modes is still available as a backup.
>>
>> It also changes the order in which colors are declared from MSB first to
>> the more standard LSB first.
>>
>> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
>> ---
>> Changes from v1:
>> - amended documentation following Stephen's suggestion
>> - allow parsing of bitfields larger than 9 bits
>> - made it clear that the parsing order of bits is changed with respect
>> to the original patch
>>
>> Andrew, since this patch introduces a (small) change in the DT bindings,
>> could we try to merge it during the -rc cycle so we don't have to come
>> with a more complex solution in the future?
>
> So, I think we shouldn't change the DT binding at all now. The original
> driver is now merged for 3.10, and I think it's far too late to take
> code that implements new features for 3.10. This means that we couldn't
> merge this patch until 3.11. However, by then, we shouldn't be changing
> the DT binding in incompatible ways. Olof has already published some
> U-Boot binaries that use the current binding, and on IRC indicated he'd
> prefer not to change the binding because of that.
>
> As such, we should either:
>
> a) Just add new entries into the format array that already exists in the
> driver. Given David's response, this might be simplest.
>
> b) Extend the DT binding in a 100% backwards-compatible way, which would
> mean defaulting the bit-order to match the existing 1 format, and adding
> a new Boolean property to indicate that the format string is specified
> in the other order.
a) is definitely simpler, so let's do that and drop this patch. Sorry
about the noise.
Alex.
^ permalink raw reply
* Re: Introduce a new helper framework for buffer synchronization
From: Maarten Lankhorst @ 2013-05-28 7:23 UTC (permalink / raw)
To: Inki Dae
Cc: 'Daniel Vetter', 'Rob Clark',
'linux-fbdev', 'YoungJun Cho',
'Kyungmin Park', 'myungjoo.ham',
'DRI mailing list', linux-arm-kernel, linux-media
In-Reply-To: <005601ce5b4d$f95e0160$ec1a0420$%dae@samsung.com>
Hey,
Op 28-05-13 04:49, Inki Dae schreef:
>
>> -----Original Message-----
>> From: Maarten Lankhorst [mailto:maarten.lankhorst@canonical.com]
>> Sent: Tuesday, May 28, 2013 12:23 AM
>> To: Inki Dae
>> Cc: 'Daniel Vetter'; 'Rob Clark'; 'linux-fbdev'; 'YoungJun Cho'; 'Kyungmin
>> Park'; 'myungjoo.ham'; 'DRI mailing list'; linux-arm-
>> kernel@lists.infradead.org; linux-media@vger.kernel.org
>> Subject: Re: Introduce a new helper framework for buffer synchronization
>>
>> Hey,
>>
>> Op 27-05-13 12:38, Inki Dae schreef:
>>> Hi all,
>>>
>>> I have been removed previous branch and added new one with more cleanup.
>>> This time, the fence helper doesn't include user side interfaces and
>> cache
>>> operation relevant codes anymore because not only we are not sure that
>>> coupling those two things, synchronizing caches and buffer access
>> between
>>> CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side is
>> a
>>> good idea yet but also existing codes for user side have problems with
>> badly
>>> behaved or crashing userspace. So this could be more discussed later.
>>>
>>> The below is a new branch,
>>>
>>> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
>> exynos.git/?h=dma-f
>>> ence-helper
>>>
>>> And fence helper codes,
>>>
>>> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
>> exynos.git/commit/?
>>> h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
>>>
>>> And example codes for device driver,
>>>
>>> https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
>> exynos.git/commit/?
>>> h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
>>>
>>> I think the time is not yet ripe for RFC posting: maybe existing dma
>> fence
>>> and reservation need more review and addition work. So I'd glad for
>> somebody
>>> giving other opinions and advices in advance before RFC posting.
>>>
>> NAK.
>>
>> For examples for how to handle locking properly, see Documentation/ww-
>> mutex-design.txt in my recent tree.
>> I could list what I believe is wrong with your implementation, but real
>> problem is that the approach you're taking is wrong.
> I just removed ticket stubs to show my approach you guys as simple as
> possible, and I just wanted to show that we could use buffer synchronization
> mechanism without ticket stubs.
The tickets have been removed in favor of a ww_context. Moving it in as a base primitive
allows more locking abuse to be detected, and makes some other things easier too.
> Question, WW-Mutexes could be used for all devices? I guess this has
> dependence on x86 gpu: gpu has VRAM and it means different memory domain.
> And could you tell my why shared fence should have only eight objects? I
> think we could need more than eight objects for read access. Anyway I think
> I don't surely understand yet so there might be my missing point.
Yes, ww mutexes are not limited in any way to x86. They're a locking mechanism.
When you acquired the ww mutexes for all buffer objects, all it does is say at
that point in time you have exclusively acquired the locks of all bo's.
After locking everything you can read the fence pointers safely, queue waits, and set a
new fence pointer on all reservation_objects. You only need a single fence
on all those objects, so 8 is plenty. Nonetheless this was a limitation of my
earlier design, and I'll dynamically allocate fence_shared in the future.
~Maarten
^ permalink raw reply
* fb_monspecs and device tree
From: Richard Genoud @ 2013-05-28 9:41 UTC (permalink / raw)
To: Steffen Trumtrar
Cc: linux-fbdev-u79uwXL29TY76Z2rM5mHXA,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ,
Florian Tobias Schandinat
Hi !
I've been using the display-timings device tree node (great job !) on
a sam9x5 soc.
I was wondering if there's a planned support for struct fb_monspecs in
device tree, (or if it is irrelevant), if someone is already working
on that etc...
Regards,
Richard.
^ permalink raw reply
* Re: Introduce a new helper framework for buffer synchronization
From: Daniel Vetter @ 2013-05-28 10:32 UTC (permalink / raw)
To: Inki Dae
Cc: 'Rob Clark', 'Maarten Lankhorst',
'Daniel Vetter', 'linux-fbdev',
'YoungJun Cho', 'Kyungmin Park',
'myungjoo.ham', 'DRI mailing list',
linux-arm-kernel, linux-media
In-Reply-To: <005701ce5b57$667c7d40$337577c0$%dae@samsung.com>
On Tue, May 28, 2013 at 12:56:57PM +0900, Inki Dae wrote:
>
>
> > -----Original Message-----
> > From: linux-fbdev-owner@vger.kernel.org [mailto:linux-fbdev-
> > owner@vger.kernel.org] On Behalf Of Rob Clark
> > Sent: Tuesday, May 28, 2013 12:48 AM
> > To: Inki Dae
> > Cc: Maarten Lankhorst; Daniel Vetter; linux-fbdev; YoungJun Cho; Kyungmin
> > Park; myungjoo.ham; DRI mailing list;
> linux-arm-kernel@lists.infradead.org;
> > linux-media@vger.kernel.org
> > Subject: Re: Introduce a new helper framework for buffer synchronization
> >
> > On Mon, May 27, 2013 at 6:38 AM, Inki Dae <inki.dae@samsung.com> wrote:
> > > Hi all,
> > >
> > > I have been removed previous branch and added new one with more cleanup.
> > > This time, the fence helper doesn't include user side interfaces and
> > cache
> > > operation relevant codes anymore because not only we are not sure that
> > > coupling those two things, synchronizing caches and buffer access
> > between
> > > CPU and CPU, CPU and DMA, and DMA and DMA with fences, in kernel side is
> > a
> > > good idea yet but also existing codes for user side have problems with
> > badly
> > > behaved or crashing userspace. So this could be more discussed later.
> > >
> > > The below is a new branch,
> > >
> > > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> > exynos.git/?h=dma-f
> > > ence-helper
> > >
> > > And fence helper codes,
> > >
> > > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> > exynos.git/commit/?
> > > h=dma-fence-helper&idcbc0fe7e285ce866e5816e5e21443dcce01005
> > >
> > > And example codes for device driver,
> > >
> > > https://git.kernel.org/cgit/linux/kernel/git/daeinki/drm-
> > exynos.git/commit/?
> > > h=dma-fence-helper&idÒce7af23835789602a99d0ccef1f53cdd5caaae
> > >
> > > I think the time is not yet ripe for RFC posting: maybe existing dma
> > fence
> > > and reservation need more review and addition work. So I'd glad for
> > somebody
> > > giving other opinions and advices in advance before RFC posting.
> >
> > thoughts from a *really* quick, pre-coffee, first look:
> > * any sort of helper to simplify single-buffer sort of use-cases (v4l)
> > probably wouldn't want to bake in assumption that seqno_fence is used.
> > * I guess g2d is probably not actually a simple use case, since I
> > expect you can submit blits involving multiple buffers :-P
>
> I don't think so. One and more buffers can be used: seqno_fence also has
> only one buffer. Actually, we have already applied this approach to most
> devices; multimedia, gpu and display controller. And this approach shows
> more performance; reduced power consumption against traditional way. And g2d
> example is just to show you how to apply my approach to device driver.
Note that seqno_fence is an implementation pattern for a certain type of
direct hw->hw synchronization which uses a shared dma_buf to exchange the
sync cookie. The dma_buf attached to the seqno_fence has _nothing_ to do
with the dma_buf the fence actually coordinates access to.
I think that confusing is a large reason for why Maarten&I don't
understand what you want to achieve with your fence helpers. Currently
they're using the seqno_fence, but totally not in a way the seqno_fence
was meant to be used.
Note that with the current code there is only a pointer from dma_bufs to
the fence. The fence itself has _no_ pointer to the dma_buf it syncs. This
shouldn't be a problem since the fence fastpath for already signalled
fences is completely barrier&lock free (it's just a load+bit-test), and
fences are meant to be embedded into whatever dma tracking structure you
already have, so no overhead there. The only ugly part is the fence
refcounting, but I don't think we can drop that.
Note that you completely reinvent this part of Maarten's fence patches by
adding new r/w_complete completions to the reservation object, which
completely replaces the fence stuff.
Also note that a list of reservation entries is again meant to be used
only when submitting the dma to the gpu. With your patches you seem to
hang onto that list until dma completes. This has the ugly side-effect
that you need to allocate these reservation entries with kmalloc, whereas
if you just use them in the execbuf ioctl to construct the dma you can
usually embed it into something else you need already anyway. At least
i915 and ttm based drivers can work that way.
Furthermore fences are specifically constructed as frankenstein-monsters
between completion/waitqueues and callbacks. All the different use-cases
need the different aspects:
- busy/idle checks and bo retiring need the completion semantics
- callbacks (in interrupt context) are used for hybrid hw->irq handler->hw
sync approaches
>
> > * otherwise, you probably don't want to depend on dmabuf, which is why
> > reservation/fence is split out the way it is.. you want to be able to
> > use a single reservation/fence mechanism within your driver without
> > having to care about which buffers are exported to dmabuf's and which
> > are not. Creating a dmabuf for every GEM bo is too heavyweight.
>
> Right. But I think we should dealt with this separately. Actually, we are
> trying to use reservation for gpu pipe line synchronization such as sgx sync
> object and this approach is used without dmabuf. In order words, some device
> can use only reservation for such pipe line synchronization and at the same
> time, fence helper or similar thing with dmabuf for buffer synchronization.
I think a quick overview of the different pieces would be in order.
- ww_mutex: This is just the locking primite which allows you to grab
multiple mutexes without the need to check for ordering (and so fear
deadlocks).
- fence: This is just a fancy kind of completion with a bit of support for
hw->hw completion events. The fences themselve have no tie-in with
buffers, ww_mutexes or anything else.
- reservation: This ties together an object (doesn't need to be a buffer,
could be any other gpu resource - see the drm/vmwgfx driver if you want
your mind blown) with fences. Note that there's no connection the other
way round, i.e. with the current patches you can't see which
reservations are using which fences. Also note that other objects than
reservations could point at fences, e.g. when the provide
shared/exclusive semantics are not good enough for your needs.
The ww_mutex in the reservation is simply the (fancy) lock which
protects each reservation. The reason we need something fancy is that
you need to lock all objects which are synced by the same fence
toghether, otherwise you can race and construct deadlocks in the hw->hw
sync part of fences.
- dma_buf integration: This is simply a pointer to the reservation object
of the underlying buffer object. We need a pointer here since otherwise
you can construct deadlocks between dma_buf objects and native buffer
objects.
The crux is also that dma_buf integration comes last - before you can do
that you need to have your driver converted over to use
ww_mutexes/fences/reservations.
I hope that helps to unconfuse things a bit and help you understand the
different pieces of the fence/reservation/ww_mutex patches floating
around.
Cheers, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
^ permalink raw reply
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