[PATCH v2 01/38] backlight/bd6107: Compare against struct fb_info.device

[PATCH v2 01/38] backlight/bd6107: Compare against struct fb_info.device

[Thomas Zimmermann]

Struct bd6107_platform_data refers to a platform device within
the Linux device hierarchy. The test in bd6107_backlight_check_fb()
compares it against the fbdev device in struct fb_info.dev, which
is different. Fix the test by comparing to struct fb_info.device.

Fixes a bug in the backlight driver and prepares fbdev for making
struct fb_info.dev optional.

v2:
	* move renames into separate patch (Javier, Sam, Michael)

Fixes: 67b43e590415 ("backlight: Add ROHM BD6107 backlight driver")
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Lee Jones <lee@kernel.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v3.12+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/backlight/bd6107.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/backlight/bd6107.c b/drivers/video/backlight/bd6107.c
index f4db6c064635b..e3410444ea235 100644
--- a/drivers/video/backlight/bd6107.c
+++ b/drivers/video/backlight/bd6107.c
@@ -104,7 +104,7 @@ static int bd6107_backlight_check_fb(struct backlight_device *backlight,
 {
 	struct bd6107 *bd = bl_get_data(backlight);
 
-	return bd->pdata->fbdev == NULL || bd->pdata->fbdev == info->dev;
+	return bd->pdata->fbdev == NULL || bd->pdata->fbdev == info->device;
 }
 
 static const struct backlight_ops bd6107_backlight_ops = {
-- 
2.41.0

[PATCH v2 03/38] backlight/gpio_backlight: Compare against struct fb_info.device

[Thomas Zimmermann]

Struct gpio_backlight_platform_data refers to a platform device within
the Linux device hierarchy. The test in gpio_backlight_check_fb()
compares it against the fbdev device in struct fb_info.dev, which
is different. Fix the test by comparing to struct fb_info.device.

Fixes a bug in the backlight driver and prepares fbdev for making
struct fb_info.dev optional.

v2:
	* move renames into separate patch (Javier, Sam, Michael)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 8b770e3c9824 ("backlight: Add GPIO-based backlight driver")
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Rich Felker <dalias@libc.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Lee Jones <lee@kernel.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: linux-sh@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v3.12+
---
 drivers/video/backlight/gpio_backlight.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index 6f78d928f054a..5c5c99f7979e3 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -35,7 +35,7 @@ static int gpio_backlight_check_fb(struct backlight_device *bl,
 {
 	struct gpio_backlight *gbl = bl_get_data(bl);
 
-	return gbl->fbdev == NULL || gbl->fbdev == info->dev;
+	return gbl->fbdev == NULL || gbl->fbdev == info->device;
 }
 
 static const struct backlight_ops gpio_backlight_ops = {
-- 
2.41.0

[PATCH v2 05/38] backlight/lv5207lp: Compare against struct fb_info.device

[Thomas Zimmermann]

Struct lv5207lp_platform_data refers to a platform device within
the Linux device hierarchy. The test in lv5207lp_backlight_check_fb()
compares it against the fbdev device in struct fb_info.dev, which
is different. Fix the test by comparing to struct fb_info.device.

Fixes a bug in the backlight driver and prepares fbdev for making
struct fb_info.dev optional.

v2:
	* move renames into separate patch (Javier, Sam, Michael)

Fixes: 82e5c40d88f9 ("backlight: Add Sanyo LV5207LP backlight driver")
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Lee Jones <lee@kernel.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: linux-sh@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v3.12+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
---
 drivers/video/backlight/lv5207lp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/backlight/lv5207lp.c b/drivers/video/backlight/lv5207lp.c
index 00673c8b66ac5..99ba4bc0a500d 100644
--- a/drivers/video/backlight/lv5207lp.c
+++ b/drivers/video/backlight/lv5207lp.c
@@ -67,7 +67,7 @@ static int lv5207lp_backlight_check_fb(struct backlight_device *backlight,
 {
 	struct lv5207lp *lv = bl_get_data(backlight);
 
-	return lv->pdata->fbdev == NULL || lv->pdata->fbdev == info->dev;
+	return lv->pdata->fbdev == NULL || lv->pdata->fbdev == info->device;
 }
 
 static const struct backlight_ops lv5207lp_backlight_ops = {
-- 
2.41.0

[PATCH v2 14/38] fbdev/ep93xx-fb: Do not assign to struct fb_info.dev

[Thomas Zimmermann]

Do not assing the Linux device to struct fb_info.dev. The call to
register_framebuffer() initializes the field to the fbdev device.
Drivers should not override its value.

Fixes a bug where the driver incorrectly decreases the hardware
device's reference counter and leaks the fbdev device.

v2:
	* add Fixes tag (Dan)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 88017bda96a5 ("ep93xx video driver")
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Cc: <stable@vger.kernel.org> # v2.6.32+
---
 drivers/video/fbdev/ep93xx-fb.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/video/fbdev/ep93xx-fb.c b/drivers/video/fbdev/ep93xx-fb.c
index f6cd200fe50ff..37309f9dbe828 100644
--- a/drivers/video/fbdev/ep93xx-fb.c
+++ b/drivers/video/fbdev/ep93xx-fb.c
@@ -474,7 +474,6 @@ static int ep93xxfb_probe(struct platform_device *pdev)
 	if (!info)
 		return -ENOMEM;
 
-	info->dev = &pdev->dev;
 	platform_set_drvdata(pdev, info);
 	fbi = info->par;
 	fbi->mach_info = mach_info;
-- 
2.41.0

Re: [PATCH v2 01/38] backlight/bd6107: Compare against struct fb_info.device

[Dan Carpenter]

On Mon, Jun 12, 2023 at 04:07:39PM +0200, Thomas Zimmermann wrote:
> Struct bd6107_platform_data refers to a platform device within
> the Linux device hierarchy. The test in bd6107_backlight_check_fb()
> compares it against the fbdev device in struct fb_info.dev, which
> is different. Fix the test by comparing to struct fb_info.device.
> 
> Fixes a bug in the backlight driver and prepares fbdev for making
> struct fb_info.dev optional.
> 
> v2:
> 	* move renames into separate patch (Javier, Sam, Michael)
> 

Thanks.  This helps a lot.  I stared at this for a long time without
seeing the fix.  Then I misunderstood Sam's review comments (my fault,
they were clear in retrospect) so I got completely lost.

regards,
dan carpenter

RE: [PATCH v2 01/38] backlight/bd6107: Compare against struct fb_info.device

[Ruhl, Michael J]

>-----Original Message-----
>From: dri-devel <dri-devel-bounces@lists.freedesktop.org> On Behalf Of
>Thomas Zimmermann
>Sent: Monday, June 12, 2023 10:08 AM
>To: daniel@ffwll.ch; javierm@redhat.com; sam@ravnborg.org;
>deller@gmx.de; geert+renesas@glider.be; lee@kernel.org;
>daniel.thompson@linaro.org; jingoohan1@gmail.com;
>dan.carpenter@linaro.org; Ruhl, Michael J <michael.j.ruhl@intel.com>
>Cc: linux-fbdev@vger.kernel.org; Laurent Pinchart
><laurent.pinchart+renesas@ideasonboard.com>; linux-sh@vger.kernel.org;
>linux-staging@lists.linux.dev; linux-kernel@vger.kernel.org; dri-
>devel@lists.freedesktop.org; stable@vger.kernel.org; Thomas Zimmermann
><tzimmermann@suse.de>; linux-omap@vger.kernel.org
>Subject: [PATCH v2 01/38] backlight/bd6107: Compare against struct
>fb_info.device
>
>Struct bd6107_platform_data refers to a platform device within
>the Linux device hierarchy. The test in bd6107_backlight_check_fb()
>compares it against the fbdev device in struct fb_info.dev, which
>is different. Fix the test by comparing to struct fb_info.device.
>
>Fixes a bug in the backlight driver and prepares fbdev for making
>struct fb_info.dev optional.
>
>v2:
>	* move renames into separate patch (Javier, Sam, Michael)
>
>Fixes: 67b43e590415 ("backlight: Add ROHM BD6107 backlight driver")
>Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
>Cc: Lee Jones <lee@kernel.org>
>Cc: Daniel Thompson <daniel.thompson@linaro.org>
>Cc: Jingoo Han <jingoohan1@gmail.com>
>Cc: dri-devel@lists.freedesktop.org
>Cc: <stable@vger.kernel.org> # v3.12+
>Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
>---
> drivers/video/backlight/bd6107.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/video/backlight/bd6107.c
>b/drivers/video/backlight/bd6107.c
>index f4db6c064635b..e3410444ea235 100644
>--- a/drivers/video/backlight/bd6107.c
>+++ b/drivers/video/backlight/bd6107.c
>@@ -104,7 +104,7 @@ static int bd6107_backlight_check_fb(struct
>backlight_device *backlight,
> {
> 	struct bd6107 *bd = bl_get_data(backlight);
>
>-	return bd->pdata->fbdev == NULL || bd->pdata->fbdev == info->dev;
>+	return bd->pdata->fbdev == NULL || bd->pdata->fbdev == info->device;

Thomas,

Looking at the fb.h file I see:

	struct device *device;		/* This is the parent */
	struct device *dev;		/* This is this fb device */

Is this documentation "correct"?  If so, how does that match what you are doing here?

Thanks,

M

> }
>
> static const struct backlight_ops bd6107_backlight_ops = {
>--
>2.41.0

Re: [PATCH v2 01/38] backlight/bd6107: Compare against struct fb_info.device

[Thomas Zimmermann]

[-- Attachment #1.1: Type: text/plain, Size: 2303 bytes --]

Hi

Am 12.06.23 um 17:17 schrieb Ruhl, Michael J:
[...]
> 
> Thomas,
> 
> Looking at the fb.h file I see:
> 
> 	struct device *device;		/* This is the parent */
> 	struct device *dev;		/* This is this fb device */
> 
> Is this documentation "correct"?  If so, how does that match what you are doing here?

The comments are correct. Let's go through what's happening here.

The field 'device' is the Linux device (platform_device, pci_dev, etc.) 
and 'dev' is the fbdev character device that is /dev/fb*.

We set 'device' where we allocate the fb_info in framebuffer_alloc()

https://elixir.bootlin.com/linux/v6.3/source/drivers/video/fbdev/core/fbsysfs.c#L57

and we set 'dev' when we register the chrdev within register_framebuffer().

https://elixir.bootlin.com/linux/v6.3/source/drivers/video/fbdev/core/fbmem.c#L1555

(And the point of this patch series is to make the chrdev optional.)

The problem with bd6107 is that is misses the part where it registers 
the platform device. The driver appears to be unused.

But gpio_backlight from patches 3 and 4 works. The architecture code 
sets the 'fbdev' field from a platform-device structure at

https://elixir.bootlin.com/linux/v6.3/source/arch/sh/boards/mach-ecovec24/setup.c#L389

and later creates the platform device as part of

https://elixir.bootlin.com/linux/v6.3/source/arch/sh/boards/mach-ecovec24/setup.c#L1483

It will be used with the sh-mobile fbdev driver and become the 'device' 
field there.

In the backlight code, the gpio_backlight driver copies the fbdev field at

https://elixir.bootlin.com/linux/v6.3/source/drivers/video/backlight/gpio_backlight.c#L62

to later use it incorrectly in .check_fb. Hence, the helper has to 
compare the platform device to the 'device' field, not the 'dev' field; 
which is being fixed by this patchset.

The two other drivers, bd6107 and lv5207lp, have the same bug.

Best regards
Thomas


> 
> Thanks,
> 
> M
> 
>> }
>>
>> static const struct backlight_ops bd6107_backlight_ops = {
>> --
>> 2.41.0
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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Re: [PATCH v2 01/38] backlight/bd6107: Compare against struct fb_info.device

[Daniel Thompson]

On Mon, Jun 12, 2023 at 04:07:39PM +0200, Thomas Zimmermann wrote:
> Struct bd6107_platform_data refers to a platform device within
> the Linux device hierarchy. The test in bd6107_backlight_check_fb()
> compares it against the fbdev device in struct fb_info.dev, which
> is different. Fix the test by comparing to struct fb_info.device.
>
> Fixes a bug in the backlight driver and prepares fbdev for making
> struct fb_info.dev optional.
>
> v2:
> 	* move renames into separate patch (Javier, Sam, Michael)
>
> Fixes: 67b43e590415 ("backlight: Add ROHM BD6107 backlight driver")
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Cc: Lee Jones <lee@kernel.org>
> Cc: Daniel Thompson <daniel.thompson@linaro.org>
> Cc: Jingoo Han <jingoohan1@gmail.com>
> Cc: dri-devel@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v3.12+
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


Daniel.

PS Please don't treat this as an Acked-by, if you want to land this
   patchset via a single tree please coordinate with Lee Jones!

Re: [PATCH v2 03/38] backlight/gpio_backlight: Compare against struct fb_info.device

[Daniel Thompson]

On Mon, Jun 12, 2023 at 04:07:41PM +0200, Thomas Zimmermann wrote:
> Struct gpio_backlight_platform_data refers to a platform device within
> the Linux device hierarchy. The test in gpio_backlight_check_fb()
> compares it against the fbdev device in struct fb_info.dev, which
> is different. Fix the test by comparing to struct fb_info.device.
>
> Fixes a bug in the backlight driver and prepares fbdev for making
> struct fb_info.dev optional.
>
> v2:
> 	* move renames into separate patch (Javier, Sam, Michael)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Fixes: 8b770e3c9824 ("backlight: Add GPIO-based backlight driver")
> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Cc: Rich Felker <dalias@libc.org>
> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> Cc: Lee Jones <lee@kernel.org>
> Cc: Daniel Thompson <daniel.thompson@linaro.org>
> Cc: Jingoo Han <jingoohan1@gmail.com>
> Cc: linux-sh@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v3.12+

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


Daniel.

Re: [PATCH v2 05/38] backlight/lv5207lp: Compare against struct fb_info.device

[Daniel Thompson]

On Mon, Jun 12, 2023 at 04:07:43PM +0200, Thomas Zimmermann wrote:
> Struct lv5207lp_platform_data refers to a platform device within
> the Linux device hierarchy. The test in lv5207lp_backlight_check_fb()
> compares it against the fbdev device in struct fb_info.dev, which
> is different. Fix the test by comparing to struct fb_info.device.
>
> Fixes a bug in the backlight driver and prepares fbdev for making
> struct fb_info.dev optional.
>
> v2:
> 	* move renames into separate patch (Javier, Sam, Michael)
>
> Fixes: 82e5c40d88f9 ("backlight: Add Sanyo LV5207LP backlight driver")
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: Rich Felker <dalias@libc.org>
> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
> Cc: Lee Jones <lee@kernel.org>
> Cc: Daniel Thompson <daniel.thompson@linaro.org>
> Cc: Jingoo Han <jingoohan1@gmail.com>
> Cc: linux-sh@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: <stable@vger.kernel.org> # v3.12+
> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>


Daniel.

Re: [PATCH v2 01/38] backlight/bd6107: Compare against struct fb_info.device

[Thomas Zimmermann]

[-- Attachment #1.1: Type: text/plain, Size: 1753 bytes --]

Hi

Am 13.06.23 um 12:37 schrieb Daniel Thompson:
> On Mon, Jun 12, 2023 at 04:07:39PM +0200, Thomas Zimmermann wrote:
>> Struct bd6107_platform_data refers to a platform device within
>> the Linux device hierarchy. The test in bd6107_backlight_check_fb()
>> compares it against the fbdev device in struct fb_info.dev, which
>> is different. Fix the test by comparing to struct fb_info.device.
>>
>> Fixes a bug in the backlight driver and prepares fbdev for making
>> struct fb_info.dev optional.
>>
>> v2:
>> 	* move renames into separate patch (Javier, Sam, Michael)
>>
>> Fixes: 67b43e590415 ("backlight: Add ROHM BD6107 backlight driver")
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
>> Cc: Lee Jones <lee@kernel.org>
>> Cc: Daniel Thompson <daniel.thompson@linaro.org>
>> Cc: Jingoo Han <jingoohan1@gmail.com>
>> Cc: dri-devel@lists.freedesktop.org
>> Cc: <stable@vger.kernel.org> # v3.12+
>> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
> 
> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>

Thanks for going through the backlight patches.

> 
> 
> Daniel.
> 
> PS Please don't treat this as an Acked-by, if you want to land this
>     patchset via a single tree please coordinate with Lee Jones!

I'd like to merge them via drm-misc-next together with the rest of the 
patchset. It's not DRM, but fbdev patches often go through that tree 
quite often.

Best regards
Thomas

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

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