Re: [Intel-gfx] [PATCH v2 6/8] drm/i915/dp: add 128b/132b support to link status checks

Ville Syrjälä
2022-02-08T15:06:33Z

On Thu, Feb 03, 2022 at 11:03:55AM +0200, Jani Nikula wrote:
> Abstract link status check to a function that takes 128b/132b and 8b/10b
> into account, and use it. Also dump link status on failures.
>
> Cc: Uma Shankar <uma.shankar@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 39 ++++++++++++++-----
> .../drm/i915/display/intel_dp_link_training.c | 2 +-
> .../drm/i915/display/intel_dp_link_training.h | 4 ++
> 3 files changed, 34 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 146b83916005..8c5590f0409a 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -3628,6 +3628,32 @@ static void intel_dp_handle_test_request(struct intel_dp *intel_dp)
> "Could not write test response to sink\n");
> }
>
> +static bool intel_dp_link_ok(struct intel_dp *intel_dp,
> + u8 link_status[DP_LINK_STATUS_SIZE])
> +{
> + struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base;
> + struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> + bool uhbr = intel_dp->link_rate >= 1000000;
> + bool ok;
> +
> + if (uhbr)
> + ok = drm_dp_128b132b_lane_channel_eq_done(link_status,
> + intel_dp->lane_count);

I was pondering whether we need to check more of the bits here. I guess
time will tell.

Remainder of the series is
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> + else
> + ok = drm_dp_channel_eq_ok(link_status, intel_dp->lane_count);
> +
> + if (ok)
> + return true;
> +
> + intel_dp_dump_link_status(intel_dp, DP_PHY_DPRX, link_status);
> + drm_dbg_kms(&i915->drm,
> + "[ENCODER:%d:%s] %s link not ok, retraining\n",
> + encoder->base.base.id, encoder->base.name,
> + uhbr ? "128b/132b" : "8b/10b");
> +
> + return false;
> +}
> +
> static void
> intel_dp_mst_hpd_irq(struct intel_dp *intel_dp, u8 *esi, u8 *ack)
> {
> @@ -3658,14 +3684,7 @@ static bool intel_dp_mst_link_status(struct intel_dp *intel_dp)
> return false;
> }
>
> - if (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count)) {
> - drm_dbg_kms(&i915->drm,
> - "[ENCODER:%d:%s] channel EQ not ok, retraining\n",
> - encoder->base.base.id, encoder->base.name);
> - return false;
> - }
> -
> - return true;
> + return intel_dp_link_ok(intel_dp, link_status);
> }
>
> /**
> @@ -3779,8 +3798,8 @@ intel_dp_needs_link_retrain(struct intel_dp *intel_dp)
> intel_dp->lane_count))
> return false;
>
> - /* Retrain if Channel EQ or CR not ok */
> - return !drm_dp_channel_eq_ok(link_status, intel_dp->lane_count);
> + /* Retrain if link not ok */
> + return !intel_dp_link_ok(intel_dp, link_status);
> }
>
> static bool intel_dp_has_connector(struct intel_dp *intel_dp,
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> index cc2b82d9114c..0686da36c428 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -712,7 +712,7 @@ static bool intel_dp_adjust_request_changed(const struct intel_crtc_state *crtc_
> return false;
> }
>
> -static void
> +void
> intel_dp_dump_link_status(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy,
> const u8 link_status[DP_LINK_STATUS_SIZE])
> {
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.h b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> index dbfb15705aaa..dc1556b46b85 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> @@ -29,6 +29,10 @@ void intel_dp_start_link_train(struct intel_dp *intel_dp,
> void intel_dp_stop_link_train(struct intel_dp *intel_dp,
> const struct intel_crtc_state *crtc_state);
>
> +void
> +intel_dp_dump_link_status(struct intel_dp *intel_dp, enum drm_dp_phy dp_phy,
> + const u8 link_status[DP_LINK_STATUS_SIZE]);
> +
> /* Get the TPSx symbol type of the value programmed to DP_TRAINING_PATTERN_SET */
> static inline u8 intel_dp_training_pattern_symbol(u8 pattern)
> {
> --
> 2.30.2

--
Ville Syrjälä
Intel