[igt-dev] [PATCH i-g-t] lib: Fix intel_get_current_physical_engine() iterator

[Tvrtko Ursulin]

On 03/06/2019 11:32, Petri Latvala wrote:
> On Mon, Jun 03, 2019 at 11:19:48AM +0100, Tvrtko Ursulin wrote:
>>
>> On 29/05/2019 14:24, Chris Wilson wrote:
>>> If we run out of engines, intel_get_current_physical_engine() degrades
>>> into an infinite loop as although it advanced the iterator, it did not
>>> update its local engine pointer.
>>
>> We had one infinite loop in there already.. AFAIR it was on one engine
>> platforms. Does the new incarnation happen actually via the
>> __for_each_physical_engine iterator or perhaps only when calling
>> intel_get_current_physical_engine after loop end? Why it wasn't seen in
>> testing?
> 
> 
> The new incarnation happens with a wedged GPU. That's a case that's
> hard to come by in testing.

1.
Colour me confused. :) How does a wedged GPU affect this loop?

2.
Are we missing a test? Wedge-do-stuff-unwedge should be easy to write.

Regards,

Tvrtko