Re: [PATCH] drm/radeon: don't init gpuvm if accel is disabled

[Oded Gabbay <oded.gabbay@amd.com>]

On 01/29/2015 03:54 PM, Deucher, Alexander wrote:
>> -----Original Message-----
>> From: Gabbay, Oded
>> Sent: Thursday, January 29, 2015 2:46 AM
>> To: Alex Deucher; dri-devel@lists.freedesktop.org
>> Cc: Deucher, Alexander; stable@vger.kernel.org
>> Subject: Re: [PATCH] drm/radeon: don't init gpuvm if accel is disabled
>>
>>
>>
>> On 01/28/2015 09:41 PM, Alex Deucher wrote:
>>> If acceleration is disabled, it does not make sense
>>> to init gpuvm since nothing will use it.  Moreover,
>>> if radeon_vm_init() gets called it uses accel to try
>>> and clear the pde tables, etc. which results in a bug.
>>>
>>> Bug:
>>> https://bugs.freedesktop.org/show_bug.cgi?id=88786
>>>
>>> Signed-off-by: Alex Deucher<alexander.deucher@amd.com>
>>> Cc:stable@vger.kernel.org
>> Alex,
>> What is accel ?
>
> If the ring tests fail and for some reason the IPs (e.g., gfx or sdma) are not available, the driver disables acceleration and basically falls back to modesetting only.
>
>> Is there a situation where accel is disabled and HSA should work ? e.g.
>> headless
>> mode ?
>
> No.  We only disable acceleration if we can't get the IPs (gfx, sdma) initialized.  Headless has nothing to do with acceleration in this context.
>
> Alex
>
OK, thanks for the explanation.

	Oded