All of lore.kernel.org
 help / color / mirror / Atom feed
* [Intel-gfx] [PATCH 1/4] drm/i915: Clear leftover DP vswing/preemphasis values before modeset
@ 2021-09-30 13:43 Ville Syrjala
  2021-09-30 13:43 ` [Intel-gfx] [PATCH 2/4] drm/i915: Call intel_ddi_init_dp_buf_reg() earlier Ville Syrjala
                   ` (5 more replies)
  0 siblings, 6 replies; 13+ messages in thread
From: Ville Syrjala @ 2021-09-30 13:43 UTC (permalink / raw)
  To: intel-gfx; +Cc: Imre Deak

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Currently we clear the leftover vswing/preemphasis values only
at the start of link training. That means the initial vswing
programming performed during modeset is going to use stale values
left over from the previous link training sequence, and then at
the start of link training we're going to reset the levels back
to 0. Seems much better to make sure we start with level 0 from
the get go.

Additionally if LTTPRs are present the leftover vswing/preemphasis
values are those of the last link in the chain, so not the values
that our PHY is even using after a successful link training sequence.

So let's make sure everything is cleared up before we start
programming anything.

Suggested-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 8f5a935b72b6..74a657ae131a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1835,6 +1835,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 void intel_dp_set_link_params(struct intel_dp *intel_dp,
 			      int link_rate, int lane_count)
 {
+	memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set));
 	intel_dp->link_trained = false;
 	intel_dp->link_rate = link_rate;
 	intel_dp->lane_count = lane_count;
-- 
2.32.0


^ permalink raw reply related	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2021-09-30 19:49 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-30 13:43 [Intel-gfx] [PATCH 1/4] drm/i915: Clear leftover DP vswing/preemphasis values before modeset Ville Syrjala
2021-09-30 13:43 ` [Intel-gfx] [PATCH 2/4] drm/i915: Call intel_ddi_init_dp_buf_reg() earlier Ville Syrjala
2021-09-30 15:51   ` Imre Deak
2021-09-30 13:43 ` [Intel-gfx] [PATCH 3/4] drm/i915: Remove DP_PORT_EN stuff from link training code Ville Syrjala
2021-09-30 16:09   ` Imre Deak
2021-09-30 16:16     ` Ville Syrjälä
2021-09-30 16:19       ` Imre Deak
2021-09-30 16:21         ` Imre Deak
2021-09-30 13:43 ` [Intel-gfx] [PATCH 4/4] drm/i915: Nuke local copies/pointers of intel_dp->DP Ville Syrjala
2021-09-30 16:15   ` Imre Deak
2021-09-30 15:25 ` [Intel-gfx] [PATCH 1/4] drm/i915: Clear leftover DP vswing/preemphasis values before modeset Imre Deak
2021-09-30 16:15 ` [Intel-gfx] ✓ Fi.CI.BAT: success for series starting with [1/4] " Patchwork
2021-09-30 19:49 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.