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

[<gregkh@linuxfoundation.org>]

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 <stable@vger.kernel.org>.

thanks,

greg k-h

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

>From c7aca235aa60d1432c95b752812d359d0dbece4f Mon Sep 17 00:00:00 2001
From: Matt Roper <matthew.d.roper@intel.com>
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().

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Testcase: kms_universal_planes.cursor-only-pipe-*
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1466196140-16336-4-git-send-email-matthew.d.roper@intel.com
Cc: stable@vger.kernel.org #v4.7+
(cherry picked from commit 43aa7e87507f519b0b2497b6fac1e894554eaef2)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index e9763a89f3d7..421c5b72464a 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -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;
 }