Re: [Nouveau] [PATCH 09/17] drm/radeon: use common fence implementation for fences

Christian König
2014-07-23T09:36:57Z

Am 23.07.2014 11:30, schrieb Daniel Vetter:
> On Wed, Jul 23, 2014 at 11:27 AM, Christian König
> <christian.koenig@amd.com> wrote:
>> You submit a job to the hardware and then block the job to wait for radeon
>> to be finished? Well than this would indeed require a hardware reset, but
>> wouldn't that make the whole problem even worse?
>>
>> I mean currently we block one userspace process to wait for other hardware
>> to be finished with a buffer, but what you are describing here blocks the
>> whole hardware to wait for other hardware which in the end blocks all
>> userspace process accessing the hardware.
> There is nothing new here with prime - if one context hangs the gpu it
> blocks everyone else on i915.
>
>> Talking about alternative approaches wouldn't it be simpler to just offload
>> the waiting to a different kernel or userspace thread?
> Well this is exactly what we'll do once we have the scheduler. But
> this is an orthogonal issue imo.

Mhm, could have the scheduler first?

Cause that sounds like reducing the necessary fence interface to just a
fence->wait function.

Christian.

> -Daniel