Re: [PATCH v2 07/21] drm/i915/dp: Recheck link state after modeset

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, May 20, 2024 at 09:58:05PM +0300, Imre Deak wrote:
> Recheck the link state after a passing link training, with a 2 sec delay
> to account for cases where the link goes bad following the link training
> and the sink doesn't report this via an HPD IRQ.
> 
> The delayed work added here will be also used by a later patch after a
> failed link training to try to retrain the link with unchanged link
> params before reducing the link params.
> 
> v2: Don't flush an uninitialized delayed work (on HDMI-only DDI ports).
> v3: Add the work to intel_digital_port instead of intel_dp.
> 
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/display/g4x_dp.c         |  7 ++++
>  drivers/gpu/drm/i915/display/intel_ddi.c      | 34 +++++++++++++++++++
>  drivers/gpu/drm/i915/display/intel_ddi.h      |  4 +++
>  .../drm/i915/display/intel_display_types.h    |  3 ++
>  drivers/gpu/drm/i915/display/intel_dp.c       |  1 +
>  .../drm/i915/display/intel_dp_link_training.c | 12 +++++--
>  6 files changed, 58 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/g4x_dp.c b/drivers/gpu/drm/i915/display/g4x_dp.c
> index 06ec04e667e32..4363e32a834df 100644
> --- a/drivers/gpu/drm/i915/display/g4x_dp.c
> +++ b/drivers/gpu/drm/i915/display/g4x_dp.c
> @@ -20,6 +20,7 @@
>  #include "intel_dp_aux.h"
>  #include "intel_dp_link_training.h"
>  #include "intel_dpio_phy.h"
> +#include "intel_ddi.h"
>  #include "intel_fifo_underrun.h"
>  #include "intel_hdmi.h"
>  #include "intel_hotplug.h"
> @@ -1241,6 +1242,10 @@ static bool ilk_digital_port_connected(struct intel_encoder *encoder)
>  
>  static void intel_dp_encoder_destroy(struct drm_encoder *encoder)
>  {
> +	struct intel_digital_port *dig_port = enc_to_dig_port(to_intel_encoder(encoder));
> +
> +	intel_ddi_flush_link_check_work(dig_port);
> +
>  	intel_dp_encoder_flush_work(encoder);
>  
>  	drm_encoder_cleanup(encoder);
> @@ -1309,6 +1314,8 @@ bool g4x_dp_init(struct drm_i915_private *dev_priv,
>  
>  	dig_port->aux_ch = AUX_CH_NONE;
>  
> +	intel_ddi_init_link_check_work(dig_port);

Using "ddi" for pre-ddi platforms is confusing. The implementation
is also in intel_ddi.c for some reason.

> +
>  	intel_connector = intel_connector_alloc();
>  	if (!intel_connector)
>  		goto err_connector_alloc;
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 170ba01786cf8..86358ec27e685 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -4360,6 +4360,7 @@ static void intel_ddi_encoder_destroy(struct drm_encoder *encoder)
>  	struct drm_i915_private *i915 = to_i915(encoder->dev);
>  	struct intel_digital_port *dig_port = enc_to_dig_port(to_intel_encoder(encoder));
>  
> +	intel_ddi_flush_link_check_work(dig_port);
>  	intel_dp_encoder_flush_work(encoder);
>  	if (intel_encoder_is_tc(&dig_port->base))
>  		intel_tc_port_cleanup(dig_port);
> @@ -4441,6 +4442,37 @@ intel_ddi_init_dp_connector(struct intel_digital_port *dig_port)
>  	return connector;
>  }
>  
> +static void intel_ddi_link_check_work_fn(struct work_struct *work)
> +{
> +	struct intel_digital_port *dig_port =
> +		container_of(work, typeof(*dig_port), check_link_work.work);
> +	struct intel_encoder *encoder = &dig_port->base;
> +	struct drm_modeset_acquire_ctx ctx;
> +	int ret;
> +
> +	intel_modeset_lock_ctx_retry(&ctx, NULL, 0, ret)
> +		if (dig_port->dp.attached_connector)
> +			ret = intel_dp_retrain_link(encoder, &ctx);
> +}
> +
> +void intel_ddi_init_link_check_work(struct intel_digital_port *dig_port)
> +{
> +	INIT_DELAYED_WORK(&dig_port->check_link_work, intel_ddi_link_check_work_fn);
> +}
> +
> +void intel_ddi_flush_link_check_work(struct intel_digital_port *dig_port)
> +{
> +	cancel_delayed_work_sync(&dig_port->check_link_work);
> +}
> +
> +void intel_ddi_queue_link_check(struct intel_digital_port *dig_port, int delay_ms)
> +{
> +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> +
> +	mod_delayed_work(i915->unordered_wq,
> +			 &dig_port->check_link_work, msecs_to_jiffies(delay_ms));
> +}
> +
>  static int intel_hdmi_reset_link(struct intel_encoder *encoder,
>  				 struct drm_modeset_acquire_ctx *ctx)
>  {
> @@ -4911,6 +4943,8 @@ void intel_ddi_init(struct drm_i915_private *dev_priv,
>  
>  	dig_port->aux_ch = AUX_CH_NONE;
>  
> +	intel_ddi_init_link_check_work(dig_port);
> +
>  	encoder = &dig_port->base;
>  	encoder->devdata = devdata;
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.h b/drivers/gpu/drm/i915/display/intel_ddi.h
> index 434de7196875a..b67714483f3cc 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.h
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.h
> @@ -15,6 +15,7 @@ struct intel_bios_encoder_data;
>  struct intel_connector;
>  struct intel_crtc;
>  struct intel_crtc_state;
> +struct intel_digital_port;
>  struct intel_dp;
>  struct intel_dpll_hw_state;
>  struct intel_encoder;
> @@ -53,6 +54,9 @@ void hsw_prepare_dp_ddi_buffers(struct intel_encoder *encoder,
>  				const struct intel_crtc_state *crtc_state);
>  void intel_wait_ddi_buf_idle(struct drm_i915_private *dev_priv,
>  			     enum port port);
> +void intel_ddi_init_link_check_work(struct intel_digital_port *dig_port);
> +void intel_ddi_flush_link_check_work(struct intel_digital_port *dig_port);
> +void intel_ddi_queue_link_check(struct intel_digital_port *dig_port, int delay_ms);
>  void intel_ddi_init(struct drm_i915_private *dev_priv,
>  		    const struct intel_bios_encoder_data *devdata);
>  bool intel_ddi_get_hw_state(struct intel_encoder *encoder, enum pipe *pipe);
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 1e44a23ca2125..9317c1ae04efe 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1880,6 +1880,9 @@ struct intel_digital_port {
>  
>  	struct intel_tc_port *tc;
>  
> +	/* Check and recover a bad link status on DP and HDMI ports. */
> +	struct delayed_work check_link_work;
> +
>  	/* protects num_hdcp_streams reference count, hdcp_port_data and hdcp_auth_status */
>  	struct mutex hdcp_mutex;
>  	/* the number of pipes using HDCP signalling out of this port */
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 120f7b420807b..8da277f0c2735 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -75,6 +75,7 @@
>  #include "intel_hotplug_irq.h"
>  #include "intel_lspcon.h"
>  #include "intel_lvds.h"
> +#include "intel_modeset_lock.h"
>  #include "intel_panel.h"
>  #include "intel_pch_display.h"
>  #include "intel_pps.h"
> 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 edc970036866a..ad1fbb150ff90 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -25,6 +25,7 @@
>  #include "intel_display_types.h"
>  #include "intel_dp.h"
>  #include "intel_dp_link_training.h"
> +#include "intel_ddi.h"
>  #include "intel_panel.h"
>  
>  #define LT_MSG_PREFIX			"[CONNECTOR:%d:%s][ENCODER:%d:%s][%s] "
> @@ -1464,6 +1465,7 @@ void intel_dp_start_link_train(struct intel_dp *intel_dp,
>  			       const struct intel_crtc_state *crtc_state)
>  {
>  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>  	bool passed;
>  
>  	/*
> @@ -1483,6 +1485,11 @@ void intel_dp_start_link_train(struct intel_dp *intel_dp,
>  	else
>  		passed = intel_dp_link_train_all_phys(intel_dp, crtc_state, lttpr_count);
>  
> +	if (passed) {
> +		intel_ddi_queue_link_check(dig_port, 2000);
> +		return;
> +	}
> +
>  	/*
>  	 * Ignore the link failure in CI
>  	 *
> @@ -1495,13 +1502,12 @@ void intel_dp_start_link_train(struct intel_dp *intel_dp,
>  	 * For test cases which rely on the link training or processing of HPDs
>  	 * ignore_long_hpd flag can unset from the testcase.
>  	 */
> -	if (!passed && i915->display.hotplug.ignore_long_hpd) {
> +	if (i915->display.hotplug.ignore_long_hpd) {
>  		lt_dbg(intel_dp, DP_PHY_DPRX, "Ignore the link failure\n");
>  		return;
>  	}
>  
> -	if (!passed)
> -		intel_dp_schedule_fallback_link_training(intel_dp, crtc_state);
> +	intel_dp_schedule_fallback_link_training(intel_dp, crtc_state);
>  }
>  
>  void intel_dp_128b132b_sdp_crc16(struct intel_dp *intel_dp,
> -- 
> 2.43.3

-- 
Ville Syrjälä
Intel