Re: [PATCH 3/6] drm/i915/gt: Skip TLB invalidations once wedged

[Tvrtko Ursulin]

On 15/06/2022 16:27, Mauro Carvalho Chehab wrote:
> From: Chris Wilson <chris.p.wilson@xxxxxxxxx>
>
> Skip all further TLB invalidations once the device is wedged and
> had been reset, as, on such cases, it can no longer process instructions
> on the GPU and the user no longer has access to the TLB's in each engine.
>
> Fixes: 7938d61591d3 ("drm/i915: Flush TLBs before releasing backing store")

Are there any real problems fixed or it's just a logical thing to do? 
Not much harm tagging it as fixes in terms of process since it is tiny 
but, again, wanting a clear picture.

Regards,

Tvrtko

> Signed-off-by: Chris Wilson <chris.p.wilson@xxxxxxxxx>
> Cc: Fei Yang <fei.yang@xxxxxxxxx>
> Cc: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Acked-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> ---
>
> See [PATCH 0/6] at: https://lore.kernel.org/all/cover.1655306128.git.mchehab@xxxxxxxxxx/
>
>   drivers/gpu/drm/i915/gt/intel_gt.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
> index 61b7ec5118f9..fb4fd5273ca4 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt.c
> @@ -1226,6 +1226,9 @@ void intel_gt_invalidate_tlbs(struct intel_gt *gt)
>   	if (I915_SELFTEST_ONLY(gt->awake == -ENODEV))
>   		return;
>   
> +	if (intel_gt_is_wedged(gt))
> +		return;
> +
>   	if (GRAPHICS_VER(i915) == 12) {
>   		regs = gen12_regs;
>   		num = ARRAY_SIZE(gen12_regs);