[CI 16/17] drm/i915/gen9: Reject display updates that exceed wm limitations (v2)

Matt Roper
2016-05-12T14:06:40Z

If we can't find any valid level 0 watermark values for the requested
atomic transaction, reject the configuration before we try to start
programming the hardware.

v2:
- Add extra debugging output when we reject level 0 watermarks so that
we can more easily debug how/why they were rejected.

Cc: Lyude Paul <cpaul@redhat.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
drivers/gpu/drm/i915/intel_pm.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 3b00e0d..5c925f3 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3306,7 +3306,22 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,

if (res_blocks >= ddb_allocation || res_lines > 31) {
*enabled = false;
- return 0;
+
+ /*
+ * If there are no valid level 0 watermarks, then we can't
+ * support this display configuration.
+ */
+ if (level) {
+ return 0;
+ } else {
+ DRM_DEBUG_KMS("Requested display configuration exceeds system watermark limitations\n");
+ DRM_DEBUG_KMS("Plane %d.%d: blocks required = %u/%u, lines required = %u/31\n",
+ to_intel_crtc(cstate->base.crtc)->pipe,
+ skl_wm_plane_id(to_intel_plane(pstate->plane)),
+ res_blocks, ddb_allocation, res_lines);
+
+ return -EINVAL;
+ }
}

*out_blocks = res_blocks;