drm/fb_helper: Disable all crtc's when initial setup fails.
diff mbox

Message ID 20171128111603.62757-1-maarten.lankhorst@linux.intel.com
State New
Headers show

Commit Message

Maarten Lankhorst Nov. 28, 2017, 11:16 a.m. UTC
Some drivers like i915 start with crtc's enabled, but with deferred
fbcon setup they were no longer disabled as part of fbdev setup.
Headless units could no longer enter pc3 state because the crtc was
still enabled.

Fix this by calling restore_fbdev_mode when we would have called
it otherwise once during initial fbdev setup.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: ca91a2758fce ("drm/fb-helper: Support deferred setup")
Cc: <stable@vger.kernel.org> # v4.14+
Reported-by: Thomas Voegtle <tv@lio96.de>
---
 drivers/gpu/drm/drm_fb_helper.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Daniel Vetter Nov. 28, 2017, 11:49 a.m. UTC | #1
On Tue, Nov 28, 2017 at 12:16:03PM +0100, Maarten Lankhorst wrote:
> Some drivers like i915 start with crtc's enabled, but with deferred
> fbcon setup they were no longer disabled as part of fbdev setup.
> Headless units could no longer enter pc3 state because the crtc was
> still enabled.
> 
> Fix this by calling restore_fbdev_mode when we would have called
> it otherwise once during initial fbdev setup.
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Fixes: ca91a2758fce ("drm/fb-helper: Support deferred setup")

Please use dim fixes to get a more complete Cc: list for regression fixes.

> Cc: <stable@vger.kernel.org> # v4.14+
> Reported-by: Thomas Voegtle <tv@lio96.de>

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

But please confirm with the reporter that it indeed fixes the issue before
pushing.
-Daniel

> ---
>  drivers/gpu/drm/drm_fb_helper.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 07374008f146..e56166334455 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1809,6 +1809,10 @@ static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
>  
>  	if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
>  		DRM_INFO("Cannot find any crtc or sizes\n");
> +
> +		/* First time: disable all crtc's.. */
> +		if (!fb_helper->deferred_setup && !READ_ONCE(fb_helper->dev->master))
> +			restore_fbdev_mode(fb_helper);
>  		return -EAGAIN;
>  	}
>  
> -- 
> 2.15.0
>
Thomas Voegtle Nov. 28, 2017, 3:13 p.m. UTC | #2
On Tue, 28 Nov 2017, Daniel Vetter wrote:

> On Tue, Nov 28, 2017 at 12:16:03PM +0100, Maarten Lankhorst wrote:
>> Some drivers like i915 start with crtc's enabled, but with deferred
>> fbcon setup they were no longer disabled as part of fbdev setup.
>> Headless units could no longer enter pc3 state because the crtc was
>> still enabled.
>>
>> Fix this by calling restore_fbdev_mode when we would have called
>> it otherwise once during initial fbdev setup.
>>
>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>> Fixes: ca91a2758fce ("drm/fb-helper: Support deferred setup")
>
> Please use dim fixes to get a more complete Cc: list for regression fixes.
>
>> Cc: <stable@vger.kernel.org> # v4.14+
>> Reported-by: Thomas Voegtle <tv@lio96.de>
>
> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>
> But please confirm with the reporter that it indeed fixes the issue before
> pushing.
> -Daniel

I re-checked the latest version of the patch and it indeed fixes the 
problem.

Thanks,

    Thomas
Maarten Lankhorst Nov. 29, 2017, 2:40 p.m. UTC | #3
Op 28-11-17 om 16:13 schreef Thomas Voegtle:
> On Tue, 28 Nov 2017, Daniel Vetter wrote:
>
>> On Tue, Nov 28, 2017 at 12:16:03PM +0100, Maarten Lankhorst wrote:
>>> Some drivers like i915 start with crtc's enabled, but with deferred
>>> fbcon setup they were no longer disabled as part of fbdev setup.
>>> Headless units could no longer enter pc3 state because the crtc was
>>> still enabled.
>>>
>>> Fix this by calling restore_fbdev_mode when we would have called
>>> it otherwise once during initial fbdev setup.
>>>
>>> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
>>> Fixes: ca91a2758fce ("drm/fb-helper: Support deferred setup")
>>
>> Please use dim fixes to get a more complete Cc: list for regression fixes.
>>
>>> Cc: <stable@vger.kernel.org> # v4.14+
>>> Reported-by: Thomas Voegtle <tv@lio96.de>
>>
>> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>>
>> But please confirm with the reporter that it indeed fixes the issue before
>> pushing.
>> -Daniel
>
> I re-checked the latest version of the patch and it indeed fixes the problem.
>
> Thanks,
>
>    Thomas
>
Pushed, thanks for the report. :)

~Maarten

Patch
diff mbox

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 07374008f146..e56166334455 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1809,6 +1809,10 @@  static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
 
 	if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
 		DRM_INFO("Cannot find any crtc or sizes\n");
+
+		/* First time: disable all crtc's.. */
+		if (!fb_helper->deferred_setup && !READ_ONCE(fb_helper->dev->master))
+			restore_fbdev_mode(fb_helper);
 		return -EAGAIN;
 	}