Re: [PATCH] drm/i915: Reject async flips with bigjoiner

["Lisovskiy, Stanislav" <stanislav.lisovskiy@intel.com>]

On Mon, Dec 11, 2023 at 10:11:34AM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Currently async flips are busted when bigjoiner is in use.
> As a short term fix simply reject async flips in that case.
> 
> Cc: stable@vger.kernel.org
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/9769
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index d955957b7d18..61053c19f4cc 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5926,6 +5926,17 @@ static int intel_async_flip_check_uapi(struct intel_atomic_state *state,
>  		return -EINVAL;
>  	}
>  
> +	/*
> +	 * FIXME: Bigjoiner+async flip is busted currently.
> +	 * Remove this check once the issues are fixed.
> +	 */
> +	if (new_crtc_state->bigjoiner_pipes) {
> +		drm_dbg_kms(&i915->drm,
> +			    "[CRTC:%d:%s] async flip disallowed with bigjoiner\n",
> +			    crtc->base.base.id, crtc->base.name);
> +		return -EINVAL;
> +	}
> +

Was recently wondering, whether should we add some kind of helper
func for that check to look more readable, i.e instead of just
checking if crtc_state->bigjoiner_pipes != 0, call smth like
is_bigjoiner_used(new_crtc_state)..

Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>

>  	for_each_oldnew_intel_plane_in_state(state, plane, old_plane_state,
>  					     new_plane_state, i) {
>  		if (plane->pipe != crtc->pipe)
> -- 
> 2.41.0
>