[PATCH 08/15] drm/i915/skl+: nv12 workaround disable WM level 1-7

Vidya Srinivas
2018-01-15T03:20:10Z

From: Mahesh Kumar <mahesh1.kumar@intel.com>

Display Workaround #0826 (SKL:ALL BXT:ALL) & #1059(CNL:A)
Hardware sometimes fails to wake memory from pkg C states fetching the
last few lines of planar YUV 420 (NV12) planes. This causes
intermittent underflow and corruption.
WA: Disable package C states or do not enable latency levels 1 through 7
(WM1 - WM7) on NV12 planes.

v2: Addressed review comments by Maarten.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Signed-off-by: Vidya Srinivas <vidya.srinivas@intel.com>
---
drivers/gpu/drm/i915/intel_pm.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 9ed507a..4d9c210 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4611,6 +4611,17 @@ static int skl_compute_plane_wm(const struct drm_i915_private *dev_priv,
}
}

+ /*
+ * Display WA #826 (SKL:ALL, BXT:ALL) & #1059 (CNL:A)
+ * disable wm level 1-7 on NV12 planes
+ */
+ if (wp->is_nv12 && (level >= 1) &&
+ (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv) ||
+ IS_CNL_REVID(dev_priv, CNL_REVID_A0, CNL_REVID_A0))) {
+ result->plane_en = false;
+ return 0;
+ }
+
result->plane_res_b = res_blocks;
result->plane_res_l = res_lines;
result->plane_en = true;