[Intel-gfx] [PATCH] drm/i915: Fix modeset locks in sanitize_watermarks()

[Chris Wilson]

Quoting Ville Syrjala (2020-01-22 20:43:29)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> We've added more internal things that use modeset locks and
> thus we need to be prepared for intel_atomic_check() grabbing
> more locks than what our initial drm_modeset_lock_all_ctx()
> took. So we're missing the backoff handling here.
> 
> Also drm_atomic_helper_duplicate_state() works against us
> by clearing state->acquire_ctx in anticipation of
> drm_atomic_helper_commit_duplicated_state() being used to
> commit the state.
> 
> We could probably just reset acquire_ctx back, but instead
> let's just rewrite the whole thing without using either of
> those "helpers". There's also no need to add any connectors
> to the state here since we just want the new watermarks
> which don't depend on connectors.
> 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Some amount of staring later, aiui the new flow is correct.
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris