FAILED: patch "[PATCH] drm/i915/gen9: Drop invalid WARN() during data rate" failed to apply to 4.7-stable tree

The patch below does not apply to the 4.7-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Matt Roper <[email protected]>
Date: Fri, 17 Jun 2016 13:42:20 -0700
Subject: [PATCH] drm/i915/gen9: Drop invalid WARN() during data rate
calculation

It's possible to have a non-zero plane mask and still wind up with a total data rate of zero. There are two cases where this can happen:

* planes are active (from the KMS point of view), but are all fully clipped (positioned offscreen)
* the only active plane on a CRTC is the cursor (which is handled independently and not counted into the general data rate computations

These are both valid display setups (although unusual), so we need to drop the WARN().

Testcase: kms_universal_planes.cursor-only-pipe-*

index e9763a89f3d7..421c5b72464a 100644
@@ -3107,8 +3107,6 @@ skl_get_total_relative_data_rate(struct intel_crtc_state *intel_cstate)
 		total_data_rate += intel_cstate->wm.skl.plane_y_data_rate[id];
 	}
 
-	WARN_ON(cstate->plane_mask && total_data_rate == 0);
-
 	return total_data_rate;
 }