There is a bug report
https://bugs.freedesktop.org/show_bug.cgi?id=91393
indicating that there are panels that do not support
link training starting with non-zero voltage swing and
pre-emphasis values.
This patch proposes to make this fast link training
feature as one module parameter. To take more conservative
approach this feature is disabled by default.
Signed-off-by: Mika Kahola <mika.kah...@intel.com>
---
drivers/gpu/drm/i915/i915_drv.h | 1 +
drivers/gpu/drm/i915/i915_params.c | 4 ++++
drivers/gpu/drm/i915/intel_dp_link_training.c | 11 ++++++++++-
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a47e0f4..dc2d5a0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2669,6 +2669,7 @@ struct i915_params {
bool verbose_state_checks;
bool nuclear_pageflip;
int edp_vswing;
+ bool enable_dp_flt;
};
extern struct i915_params i915 __read_mostly;
diff --git a/drivers/gpu/drm/i915/i915_params.c
b/drivers/gpu/drm/i915/i915_params.c
index 835d609..aea5d47 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -56,6 +56,7 @@ struct i915_params i915 __read_mostly = {
.edp_vswing = 0,
.enable_guc_submission = false,
.guc_log_level = -1,
+ .enable_dp_flt = false,
};
module_param_named(modeset, i915.modeset, int, 0400);
@@ -202,3 +203,6 @@ MODULE_PARM_DESC(enable_guc_submission, "Enable GuC
submission (default:false)")
module_param_named(guc_log_level, i915.guc_log_level, int, 0400);
MODULE_PARM_DESC(guc_log_level,
"GuC firmware logging level (-1:disabled (default), 0-3:enabled)");
+
+module_param_named_unsafe(enable_dp_flt, i915.enable_dp_flt, bool, 0400);
+MODULE_PARM_DESC(enable_dp_flt, "Enable DP fast link training
(default:false)");
diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c
b/drivers/gpu/drm/i915/intel_dp_link_training.c
index 8888793..f8b6d69 100644
--- a/drivers/gpu/drm/i915/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
@@ -85,8 +85,17 @@ static bool
intel_dp_reset_link_train(struct intel_dp *intel_dp,
uint8_t dp_train_pat)
{
- if (!intel_dp->train_set_valid)
+ if (i915.enable_dp_flt) {
+ DRM_DEBUG_KMS("DP flt enabled, train set valid: %s\n",
+ intel_dp->train_set_valid ? "true" : "false");
+
+ if (!intel_dp->train_set_valid)
+ memset(intel_dp->train_set, 0,
sizeof(intel_dp->train_set));
+ } else {
+ DRM_DEBUG_KMS("DP flt disabled\n");
memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set));
+ }
+
intel_dp_set_signal_levels(intel_dp);
return intel_dp_set_link_train(intel_dp, dp_train_pat);
}
--
1.9.1
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