Noticed that we assume the best case of 0 latency when the DPCD read
fails, reasonable pessimism is safer.
eDP spec does say that if latency is greater than 8, the panel
supplier needs to provide it. I didn't see anything specific in the VBT
for this, so let's go with 8 frames as a fallback.
Cc: Jose Roberto de Souza <jose.souza@xxxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_psr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
index 381dbdbf30f4..b4a4f5d3a2bb 100644
--- a/drivers/gpu/drm/i915/intel_psr.c
+++ b/drivers/gpu/drm/i915/intel_psr.c
@@ -223,13 +223,13 @@ static bool intel_dp_get_alpm_status(struct intel_dp *intel_dp)
static u8 intel_dp_get_sink_sync_latency(struct intel_dp *intel_dp)
{
- u8 val = 0;
+ u8 val = 8; /* assume the worst if we can't read the value */
if (drm_dp_dpcd_readb(&intel_dp->aux,
DP_SYNCHRONIZATION_LATENCY_IN_SINK, &val) == 1)
val &= DP_MAX_RESYNC_FRAME_COUNT_MASK;
else
- DRM_ERROR("Unable to get sink synchronization latency\n");
+ DRM_DEBUG_KMS("Unable to get sink synchronization latency, assuming 8 frames\n");
return val;
}
--
2.14.1
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