[Intel-gfx] [PATCH v2] drm/i915/gt: Allow clobbering gpu resets if the display is off

[Chris Wilson]

Quoting Chris Wilson (2019-09-11 11:19:59)
> If the display is inactive, we need not worry about the gpu reset
> clobbering the display! To prevent the display changing state between us
> checking the active state and doing the hard reset, we introduce the
> lightweight reset lock to the atomic commit for the affected (legacy)
> platforms.

> +       /* Prevent starting a GPU reset while we change global display state */
> +       srcu = -ENODEV;
> +       if (INTEL_INFO(dev_priv)->gpu_reset_clobbers_display)
> +               /* only fails if interrupted */
> +               srcu = intel_gt_reset_trylock(&dev_priv->gt);

This is overkill? Before starting the GPU reset, we serialise with the
modeset, do we not?
-Chris