> -----Original Message-----
> From: Nautiyal, Ankit K <ankit.k.nautiyal@xxxxxxxxx>
> Sent: Sunday, November 1, 2020 3:37 PM
> To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx; Shankar, Uma <uma.shankar@xxxxxxxxx>;
> Kulkarni, Vandita <vandita.kulkarni@xxxxxxxxx>; ville.syrjala@xxxxxxxxxxxxxxx;
> Sharma, Swati2 <swati2.sharma@xxxxxxxxx>
> Subject: [PATCH v2 10/13] drm/i915: Add support for enabling link status and
> recovery
>
> From: Swati Sharma <swati2.sharma@xxxxxxxxx>
>
> In this patch enables support for detecting link failures between PCON and HDMI
> sink in i915 driver. HDMI link loss indication to upstream DP source is indicated
> via IRQ_HPD. This is followed by reading of HDMI link configuration status
> (HDMI_TX_LINK_ACTIVE_STATUS).
> If the PCON → HDMI 2.1 link status is off; reinitiate frl link training to recover.
> Also, report HDMI FRL link error count range for each individual FRL active lane is
> indicated by DOWNSTREAM_HDMI_ERROR_STATUS_LN registers.
>
> v2: Checked for dpcd read and write failures and added debug message.
> (Uma Shankar)
Reviewed-by: Uma Shankar <uma.shankar@xxxxxxxxx>
> Signed-off-by: Swati Sharma <swati2.sharma@xxxxxxxxx>
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 56 +++++++++++++++++++++++--
> 1 file changed, 53 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 9047b620c0d0..6177169c4401 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5932,6 +5932,31 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
> return link_ok;
> }
>
> +static void
> +intel_dp_handle_hdmi_link_status_change(struct intel_dp *intel_dp) {
> + bool is_active;
> + u8 buf = 0;
> +
> + is_active = drm_dp_pcon_hdmi_link_active(&intel_dp->aux);
> + if (intel_dp->frl.is_trained && !is_active) {
> + if (drm_dp_dpcd_readb(&intel_dp->aux,
> DP_PCON_HDMI_LINK_CONFIG_1, &buf) < 0)
> + return;
> +
> + buf &= ~DP_PCON_ENABLE_HDMI_LINK;
> + if (drm_dp_dpcd_writeb(&intel_dp->aux,
> DP_PCON_HDMI_LINK_CONFIG_1, buf) < 0)
> + return;
> +
> + drm_dp_pcon_hdmi_frl_link_error_count(&intel_dp->aux,
> +&intel_dp->attached_connector->base);
> +
> + intel_dp->frl.is_trained = false;
> + intel_dp->frl.trained_rate_gbps = 0;
> +
> + /* Restart FRL training or fall back to TMDS mode */
> + intel_dp_check_frl_training(intel_dp);
> + }
> +}
> +
> static bool
> intel_dp_needs_link_retrain(struct intel_dp *intel_dp) { @@ -6297,7 +6322,7
> @@ intel_dp_hotplug(struct intel_encoder *encoder,
> return state;
> }
>
> -static void intel_dp_check_service_irq(struct intel_dp *intel_dp)
> +static void intel_dp_check_device_service_irq(struct intel_dp
> +*intel_dp)
> {
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> u8 val;
> @@ -6321,6 +6346,30 @@ static void intel_dp_check_service_irq(struct intel_dp
> *intel_dp)
> drm_dbg_kms(&i915->drm, "Sink specific irq unhandled\n"); }
>
> +static void intel_dp_check_link_service_irq(struct intel_dp *intel_dp)
> +{
> + struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> + u8 val;
> +
> + if (intel_dp->dpcd[DP_DPCD_REV] < 0x11)
> + return;
> +
> + if (drm_dp_dpcd_readb(&intel_dp->aux,
> + DP_LINK_SERVICE_IRQ_VECTOR_ESI0, &val) != 1 ||
> !val) {
> + drm_dbg_kms(&i915->drm, "Error in reading link service irq
> vector\n");
> + return;
> + }
> +
> + if (drm_dp_dpcd_writeb(&intel_dp->aux,
> + DP_LINK_SERVICE_IRQ_VECTOR_ESI0, val) != 1) {
> + drm_dbg_kms(&i915->drm, "Error in writing link service irq
> vector\n");
> + return;
> + }
> +
> + if (val & HDMI_LINK_STATUS_CHANGED)
> + intel_dp_handle_hdmi_link_status_change(intel_dp);
> +}
> +
> /*
> * According to DP spec
> * 5.1.2:
> @@ -6360,7 +6409,8 @@ intel_dp_short_pulse(struct intel_dp *intel_dp)
> return false;
> }
>
> - intel_dp_check_service_irq(intel_dp);
> + intel_dp_check_device_service_irq(intel_dp);
> + intel_dp_check_link_service_irq(intel_dp);
>
> /* Handle CEC interrupts, if any */
> drm_dp_cec_irq(&intel_dp->aux);
> @@ -6794,7 +6844,7 @@ intel_dp_detect(struct drm_connector *connector,
> to_intel_connector(connector)->detect_edid)
> status = connector_status_connected;
>
> - intel_dp_check_service_irq(intel_dp);
> + intel_dp_check_device_service_irq(intel_dp);
>
> out:
> if (status != connector_status_connected && !intel_dp->is_mst)
> --
> 2.17.1
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