[Intel-gfx] [CI 04/20] drm/i915: Remove the dedicated hangcheck workqueue

[Tvrtko Ursulin]

On 19/05/16 14:13, Chris Wilson wrote:
> On Thu, May 19, 2016 at 01:50:51PM +0100, Tvrtko Ursulin wrote:
>>
>> On 19/05/16 12:32, Chris Wilson wrote:
>>> The queue only ever contains at most one item and has no special flags.
>>> It is just a very simple wrapper around the system-wq - a complication
>>> with no benefits.
>>
>> How much time do we take in the reset case - is it acceptable to do
>> that work from the system wq?
>
> Hangcheck is a handful of register reads and some pointer chasing per
> engine. (There is a seqno_barrier in there which may be reasonably
> expensive but not a cpu hog). The error capture is run from the
> hangcheck context - and that is no small task (especially if we ever
> apply the object compression patches), but for safety we need to call
> stop_machine() so it really doesn't matter at that point.

I don't see a stop_machine? So until there is one, using the system wq 
is a bit impolite in the error capture state, agreed?

Regards,

Tvrtko