[Intel-gfx] 4.2-rc2 regression: drm/i915

[Daniel Vetter]

Can you please attach your Xorg.log?

Thanks, Daniel

On Tue, Jul 14, 2015 at 6:51 AM, Harald Arnesen <harald at skogtun.org> wrote:
> 4.2-rc2 gives me an unusable X11 screen (se attached picture).
> 4.2-rc1 is OK.
>
> Bisected to the following:
>
>
> 19ee835cdb0b5a8eb11a68f25a51b8039d564488 is the first bad commit
> commit 19ee835cdb0b5a8eb11a68f25a51b8039d564488
> Author: Chris Wilson <chris at chris-wilson.co.uk>
> Date:   Mon Jun 29 14:01:19 2015 +0100
>
>     drm/i915: Declare the swizzling unknown for L-shaped configurations
>
>     The old style of memory interleaving swizzled upto the end of the
>     first even bank of memory, and then used the remainder as unswizzled on
>     the unpaired bank - i.e. swizzling is not constant for all memory. This
>     causes problems when we try to migrate memory and so the kernel prevents
>     migration at all when we detect L-shaped inconsistent swizzling.
>     However, this issue also extends to userspace who try to manually detile
>     into memory as the swizzling for an individual page is unknown (it
>     depends on its physical address only known to the kernel), userspace
>     cannot correctly swizzle objects.
>
>     v2: Mark the global swizzling as unknown rather than adjust the value
>     reported to userspace.
>
>     Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91105
>     Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>     Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
>     Cc: stable at vger.kernel.org
>     Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>
> :040000 040000 a34dedabcb878bfc55ce76c231d60fc801f79319
> 3e45d34152a15df5cf07fa50e6720c9948ed8a6a M      drivers
>
>
>
> And indeed, if I revert this commit, 4.2-rc2 is OK as well.
> Kernel config and dmesg from rc1 and rc2 is attached.
> --
> Hilsen Harald



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch