'commit 97173eaf5 ("drm/i915: PSR: Increase idle_frames")' was a mistake.
The special case it tried to cover was already being covered by
the DP_PSR_NO_TRAIN_ON_EXIT. So this ended up duplicated.
So, instead of reverting that let's take this opportunity and unify
the idle_frame definition in a single place so we standardize the access
and avoid room for that same mistake again.
Few changes with this patch:
1. Instead of just respecting the VBT we set a
global minumum with max(). So we are sure that we will avoid corner cases
in case VBT is doing something we don't understand.
2. Instead of minimum 5 we use 6. When introducing the idle_frames += 4 case
we considered that minimum was 2. All because the off-by-one issue.
v2: Unified idle_frame definition.
Cc: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_psr.c | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 3a10263..f12fc56 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -267,23 +267,17 @@ static void hsw_psr_enable_source(struct intel_dp *intel_dp)
struct drm_i915_private *dev_priv = dev->dev_private;
uint32_t max_sleep_time = 0x1f;
- /* Lately it was identified that depending on panel idle frame count
- * calculated at HW can be off by 1. So let's use what came
- * from VBT + 1.
- * There are also other cases where panel demands at least 4
- * but VBT is not being set. To cover these 2 cases lets use
- * at least 5 when VBT isn't set to be on the safest side.
+ /*
+ * Let's respect VBT in case VBT asks a higher idle_frame value.
+ * Let's use 6 as the minimum to cover all known cases including
+ * the off-by-one issue that HW has in some cases. Also there are
+ * cases where sink should be able to train
+ * with the 5 or 6 idle patterns.
*/
- uint32_t idle_frames = dev_priv->vbt.psr.idle_frames ?
- dev_priv->vbt.psr.idle_frames + 1 : 5;
+ uint32_t idle_frames = max(6, dev_priv->vbt.psr.idle_frames);
uint32_t val = 0x0;
const uint32_t link_entry_time = EDP_PSR_MIN_LINK_ENTRY_TIME_8_LINES;
- if (intel_dp->psr_dpcd[1] & DP_PSR_NO_TRAIN_ON_EXIT) {
- /* Sink should be able to train with the 5 or 6 idle patterns */
- idle_frames += 4;
- }
-
I915_WRITE(EDP_PSR_CTL, val |
(IS_BROADWELL(dev) ? 0 : link_entry_time) |
max_sleep_time << EDP_PSR_MAX_SLEEP_TIME_SHIFT |
--
2.4.3
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