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+

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d74c26f1cf77ee1d0a629cf91d03507168d039f0..8a6751e14ab9b72e9c4b6dc04ad489170cc43739 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3115,8 +3115,6 @@ 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;
 }