[Intel-gfx] [PATCH v2] drm/i915/skl: Increase ddb blocks to support large cursor sizes

Radhakrishna Sripada radhakrishna.sripada at intel.com
Fri Dec 18 15:58:52 PST 2015

Original value of 32 blocks is not sufficient when using cursor size of
256x256 causing FIFO underruns when the reworked wm
caluclations in

commit 024c9045221fe45482863c47c4b4c47d37f97cbf
Author: Matt Roper <matthew.d.roper at intel.com>
Date:   Thu Sep 24 15:53:11 2015 -0700

    drm/i915/skl: Eliminate usage of pipe_wm_parameters from SKL-style WM (v4)

are used. Increasing the number of blocks to 52 to make cursor plane tolerate
SAGV block time for the maximum possible cursor size.

v2: Included Matt's suggestion, bumping up the no of blocks in multi-pipe case
to 16.

Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
Signed-off-by: Kalyan Kondapally <kalyan.kondapally at intel.com>
 drivers/gpu/drm/i915/intel_pm.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index d385d99..c5ba4e5 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2802,9 +2802,9 @@ skl_ddb_get_pipe_allocation_limits(struct drm_device *dev,
 static unsigned int skl_cursor_allocation(const struct intel_wm_config *config)
 	if (config->num_pipes_active == 1)
-		return 32;
+		return 52;
-	return 8;
+	return 16;
 static void skl_ddb_entry_init_from_hw(struct skl_ddb_entry *entry, u32 reg)

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