[Intel-gfx] [PATCH 03/24] drm/i915/gt: Cancel the preemption timeout on responding to it

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> We currently presume that the engine reset is successful, cancelling the
> expired preemption timer in the process. However, engine resets can
> fail, leaving the timeout still pending and we will then respond to the
> timeout again next time the tasklet fires. What we want is for the
> failed engine reset to be promoted to a full device reset, which is
> kicked by the heartbeat once the engine stops processing events.
>
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1168
> Fixes: 3a7a92aba8fb ("drm/i915/execlists: Force preemption")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: <stable at vger.kernel.org> # v5.5+

Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

> ---
>  drivers/gpu/drm/i915/gt/intel_lrc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 1d209a8a95e8..7f25894e41d5 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -3209,8 +3209,10 @@ static void execlists_submission_tasklet(unsigned long data)
>  		spin_unlock_irqrestore(&engine->active.lock, flags);
>  
>  		/* Recheck after serialising with direct-submission */
> -		if (unlikely(timeout && preempt_timeout(engine)))
> +		if (unlikely(timeout && preempt_timeout(engine))) {
> +			cancel_timer(&engine->execlists.preempt);
>  			execlists_reset(engine, "preemption time out");
> +		}
>  	}
>  }
>  
> -- 
> 2.20.1
>
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