[Intel-gfx] [PATCH 09/13] drm/i915/tc: Avoid using legacy AUX PW in TBT mode

[Souza, Jose]

On Tue, 2021-09-21 at 03:23 +0300, Imre Deak wrote:
> For the ADL-P TBT mode the spec doesn't require blocking TC-cold by
> using the legacy AUX power domain. To avoid the timeouts that this would
> cause during PHY disconnect/reconnect sequences (which will be more
> frequent after a follow-up change) use the TC_COLD_OFF power domain in
> TBT mode on all platforms. On TGL this power domain blocks TC-cold via a
> PUNIT command, while on other platforms the domain just takes a runtime
> PM reference.
> 
> If the HPD live status indicates that the port mode needs to be reset
> - for instance after switching from TBT to a DP-alt sink - still take
> the AUX domain, since the IOM firmware handshake requires this.

Reviewed-by: José Roberto de Souza <jose.souza at intel.com>

> 
> Cc: José Roberto de Souza <jose.souza at intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_tc.c | 55 ++++++++++++++++---------
>  1 file changed, 36 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> index 24d2dc2e19a7d..b2a3d297bfc19 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.c
> +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> @@ -59,10 +59,10 @@ bool intel_tc_cold_requires_aux_pw(struct intel_digital_port *dig_port)
>  static enum intel_display_power_domain
>  tc_cold_get_power_domain(struct intel_digital_port *dig_port, enum tc_port_mode mode)
>  {
> -	if (intel_tc_cold_requires_aux_pw(dig_port))
> -		return intel_legacy_aux_to_power_domain(dig_port->aux_ch);
> -	else
> +	if (mode == TC_PORT_TBT_ALT || !intel_tc_cold_requires_aux_pw(dig_port))
>  		return POWER_DOMAIN_TC_COLD_OFF;
> +
> +	return intel_legacy_aux_to_power_domain(dig_port->aux_ch);
>  }
>  
>  static intel_wakeref_t
> @@ -624,6 +624,36 @@ static void intel_tc_port_reset_mode(struct intel_digital_port *dig_port,
>  		    tc_port_mode_name(dig_port->tc_mode));
>  }
>  
> +static bool intel_tc_port_needs_reset(struct intel_digital_port *dig_port)
> +{
> +	return intel_tc_port_get_target_mode(dig_port) != dig_port->tc_mode;
> +}
> +
> +static void intel_tc_port_update_mode(struct intel_digital_port *dig_port,
> +				      int required_lanes, bool force_disconnect)
> +{
> +	enum intel_display_power_domain domain;
> +	intel_wakeref_t wref;
> +	bool needs_reset = force_disconnect;
> +
> +	if (!needs_reset) {
> +		/* Get power domain required to check the hotplug live status. */
> +		wref = tc_cold_block(dig_port, &domain);
> +		needs_reset = intel_tc_port_needs_reset(dig_port);
> +		tc_cold_unblock(dig_port, domain, wref);
> +	}
> +
> +	if (!needs_reset)
> +		return;
> +
> +	/* Get power domain required for resetting the mode. */
> +	wref = tc_cold_block_in_mode(dig_port, TC_PORT_DISCONNECTED, &domain);
> +
> +	intel_tc_port_reset_mode(dig_port, required_lanes, force_disconnect);
> +
> +	tc_cold_unblock(dig_port, domain, wref);
> +}
> +
>  static void
>  intel_tc_port_link_init_refcount(struct intel_digital_port *dig_port,
>  				 int refcount)
> @@ -670,11 +700,6 @@ void intel_tc_port_sanitize(struct intel_digital_port *dig_port)
>  	mutex_unlock(&dig_port->tc_lock);
>  }
>  
> -static bool intel_tc_port_needs_reset(struct intel_digital_port *dig_port)
> -{
> -	return intel_tc_port_get_target_mode(dig_port) != dig_port->tc_mode;
> -}
> -
>  /*
>   * The type-C ports are different because even when they are connected, they may
>   * not be available/usable by the graphics driver: see the comment on
> @@ -714,18 +739,10 @@ static void __intel_tc_port_lock(struct intel_digital_port *dig_port,
>  
>  	mutex_lock(&dig_port->tc_lock);
>  
> -	if (!dig_port->tc_link_refcount) {
> -		enum intel_display_power_domain domain;
> -		intel_wakeref_t tc_cold_wref;
>  
> -		tc_cold_wref = tc_cold_block(dig_port, &domain);
> -
> -		if (force_disconnect || intel_tc_port_needs_reset(dig_port))
> -			intel_tc_port_reset_mode(dig_port, required_lanes,
> -						 force_disconnect);
> -
> -		tc_cold_unblock(dig_port, domain, tc_cold_wref);
> -	}
> +	if (!dig_port->tc_link_refcount)
> +		intel_tc_port_update_mode(dig_port, required_lanes,
> +					  force_disconnect);
>  
>  	drm_WARN_ON(&i915->drm, dig_port->tc_mode == TC_PORT_DISCONNECTED);
>  	drm_WARN_ON(&i915->drm, dig_port->tc_mode != TC_PORT_TBT_ALT &&