[Powerpc] Sam460ex Canyonlands issue -Kernel 4.4.6-rc1

[Julian Margetson]

On 3/29/2016 11:49 PM, Michel Dänzer wrote:
> On 29.03.2016 18:55, Julian Margetson wrote:
>> On 3/28/2016 11:15 PM, Michel Dänzer wrote:
>>> On 29.03.2016 08:47, Julian Margetson wrote:
>>>> Seeing the following when booting kernel 4.6-rc1 on Acube Sam460ex
>>>> Canyonlands board.
>>>> This loops for a few times then the kernel boots.
>>>> No problem with the 4.6-rc1 with an A-eon Tabor Freescale e500v2 board.
>>>>
>>>> Regards
>>>>
>>>> Julian
>>>>
>>>>
>>>>    [    2.197839] ------------[ cut here ]------------
>>>>    [    2.197850] WARNING: CPU: 0 PID: 1 at
>>>> drivers/gpu/drm/drm_irq.c:1368 drm_vblank_off+0x2c/0x1e0
>>> That's
>>>
>>>      if (WARN_ON(pipe >= dev->num_crtcs))
>>>
>>> My best guess is that drm_vblank_off is called before drm_vblank_init,
>>> so dev->num_crtcs is still 0.
>>>
>>>
>>> Please provide the full dmesg output corresponding to the problem.
>>>
>>>
>> Attached
> [...]
>
>> [drm] radeon: irq initialized.
>> [drm:r600_ring_test] *ERROR* radeon: ring 0 test failed (scratch(0x850C)=0xCAFEDEAD)
>> radeon 0001:81:00.0: disabling GPU acceleration
> Okay, so the problem is that acceleration fails to initialize, in which
> case the driver calls drm_vblank_cleanup.
>
> I can see two basic options for a solution: Either don't call
> radeon_irq_kms_fini/drm_vblank_cleanup if acceleration fails to
> initialize, or check if acceleration is enabled before calling
> drm_vblank_on/off. Any preferences?
>
>
Thanks

No preferences .
I would be interested in a fix for the acceleration problem if possible .
I am willing to test to try to  determine the exact cause if you would 
direct me .

Regards
Julian