[Intel-gfx] [PATCH v4 1/3] drm/i915/gt: Ignore TLB invalidations on idle engines

[Tvrtko Ursulin]

On 11/05/2022 02:11, Andi Shyti wrote:
> From: Chris Wilson <chris at chris-wilson.co.uk>
> 
> As an extension of the current skip TLB invalidations if the device is
> powered down, we recognised that prior to any engine activity, all the
> TLBs are explicitly invalidated. Thus anytime we know the engine is
> asleep, we can skip invalidating the TLBs on that engine.

I've only noticed this after looking at the single patch version.

The commit message here does not match the patch really and CI also says 
something is not quite right.

Otherwise the idea I think is a good one. I think it can work together 
with the optimisation I mentioned in my reply to the single patch version.

But there is no rush, for_each_gt flow is unreachable in upstream anyway.

Regards,

Tvrtko

> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Andi Shyti <andi.shyti at linux.intel.com>
> ---
>   drivers/gpu/drm/i915/gt/intel_gt_pm.h | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm.h b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> index bc898df7a48cc..3b1fbce7ea369 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm.h
> @@ -55,6 +55,10 @@ static inline void intel_gt_pm_might_put(struct intel_gt *gt)
>   	for (tmp = 1, intel_gt_pm_get(gt); tmp; \
>   	     intel_gt_pm_put(gt), tmp = 0)
>   
> +#define with_intel_gt_pm_if_awake(gt, tmp) \
> +	for (tmp = 1, intel_gt_pm_get_if_awake(gt); tmp; \
> +	     intel_gt_pm_put(gt), tmp = 0)
> +
>   static inline int intel_gt_pm_wait_for_idle(struct intel_gt *gt)
>   {
>   	return intel_wakeref_wait_for_idle(&gt->wakeref);