Re: [RFC 10/11] drm/i915: Debugfs interface for per-engine hang recovery.

Dave Gordon
2015-06-11T09:32:19Z

On 08/06/15 18:45, Chris Wilson wrote:
> On Mon, Jun 08, 2015 at 06:03:28PM +0100, Tomas Elf wrote:
>> 1. The i915_wedged_set function allows us to schedule three forms of hang recovery:
>>
>> a) Legacy hang recovery: By passing e.g. -1 we trigger the legacy full
>> GPU reset recovery path.
>>
>> b) Single engine hang recovery: By passing an engine ID in the interval
>> of [0, I915_NUM_RINGS) we can schedule hang recovery of any single
>> engine assuming that the context submission consistency requirements
>> are met (otherwise the hang recovery path will simply exit early and
>> wait for another hang detection). The values are assumed to use up bits
>> 3:0 only since we certainly do not support as many as 16 engines.
>>
>> This mode is supported since there are several legacy test applications
>> that rely on this interface.
>
> Are there? I don't see them in igt - and let's not start making debugfs
> ABI.

AFAIK there are currently only two meaningful values to write to
i915_wedged: zero, which triggers error capture without resetting, and
any non-zero value, which triggers error capture followed by reset.

.Dave.