linux-kernel - Re: linux-next: Tree for Aug 13 [ screen corruption in graphical mode ]

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Date:	Tue, 13 Aug 2013 19:03:44 +0200
From:	Sedat Dilek <sedat.dilek@...il.com>
To:	Chris Wilson <chris@...is-wilson.co.uk>,
	Sedat Dilek <sedat.dilek@...il.com>,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	linux-next@...r.kernel.org, linux-kernel@...r.kernel.org,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Dave Airlie <airlied@...il.com>,
	DRI <dri-devel@...ts.freedesktop.org>,
	intel-gfx <intel-gfx@...ts.freedesktop.org>,
	"s.dilek" <s.dilek@...erlin.de>
Subject: Re: linux-next: Tree for Aug 13 [ screen corruption in graphical mode ]

On Tue, Aug 13, 2013 at 6:37 PM, Sedat Dilek <sedat.dilek@...il.com> wrote:
> On Tue, Aug 13, 2013 at 6:34 PM, Chris Wilson <chris@...is-wilson.co.uk> wrote:
>> On Tue, Aug 13, 2013 at 06:23:29PM +0200, Sedat Dilek wrote:
>>> On Tue, Aug 13, 2013 at 5:59 PM, Sedat Dilek <sedat.dilek@...il.com> wrote:
>>> > I have bisected the issue on Linux v3.11-rc5 + drm-intel-nightly:
>>> >
>>> > 5456fe3882812aba251886e36fe55bfefb8e8829 is the first bad commit
>>> > commit 5456fe3882812aba251886e36fe55bfefb8e8829
>>> > Author: Chris Wilson <chris@...is-wilson.co.uk>
>>> > Date:   Thu Aug 8 14:41:07 2013 +0100
>>> >
>>> >     drm/i915: Allocate LLC ringbuffers from stolen
>>> >
>>> >     As stolen objects now behave identically (wrt to default LLC cacheing)
>>> >     as their normal system counterparts, we no longer have to differentiate
>>> >     our usage for ringbuffers. So allocate them from stolen on SNB+ as well.
>>> >
>>> >     Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
>>> >     Reviewed-by: Ville Syrjälä <ville.syrjala@...ux.intel.com>
>>> >     Signed-off-by: Daniel Vetter <daniel.vetter@...ll.ch>
>>> >
>>> > :040000 040000 de063a052f39095f4d2f51b49caef9f827df41e8
>>> > 1c819aa5501a9fcc9912a5c7c037c71b9b9e9a6b M      drivers
>>> >
>>> > See also attached files!
>>> >
>>>
>>> With the attached revert-patch my system is OK (with my customized X stack).
>>
>> No indication of a GPU hang? I'm puzzled as to how this ends up with the
>> scanout being misread.
>>
>> cat /sys/kernel/debug/dri/0/i915_gem_stolen
>> cat /sys/kernel/debug/dri/0/i915_gem_framebuffer
>>
>> would be interesting.
>
> With revert-patch applied:
>
> $ sudo cat /sys/kernel/debug/dri/0/i915_gem_stolen
> Stolen:
>    ffff88007f6f5200: p g     4128KiB 77 00 0 0 0 uncached (name: 1)
> (pinned x 1) (display) (ggtt offset: 00072000, size: 00408000)
> (stolen: 00000000) (p mappable)
> Total 1 objects, 4227072 bytes, 4227072 GTT size
>
> $ sudo cat /sys/kernel/debug/dri/0/i915_gem_framebuffer
> fbcon size: 1366 x 768, depth 24, 32 bpp, refcount 2, obj
> ffff88007f6f5200: p g     4128KiB 77 00 0 0 0 uncached (name: 1)
> (pinned x 1) (display) (ggtt offset: 00072000, size: 00408000)
> (stolen: 00000000) (p mappable)
> user size: 1366 x 768, depth 24, 32 bpp, refcount 3, obj
> ffff88007f6f5080: pXg     5120KiB 36 02 124873 124873 0 uncached dirty
> (name: 3) (pinned x 1) (display) (fence: 0) (ggtt offset: 0047a000,
> size: 00500000) (p mappable) (blitter ring)
>

Attached both outputs with GOOD and BAD (BROKEN) kernel.

- Sedat -

View attachment "i915_gem_framebuffer.txt" of type "text/plain" (458 bytes)

View attachment "i915_gem_framebuffer_BROKEN.txt" of type "text/plain" (454 bytes)

View attachment "i915_gem_stolen.txt" of type "text/plain" (220 bytes)

View attachment "i915_gem_stolen_BROKEN.txt" of type "text/plain" (685 bytes)