RE: [PATCH 01/19] drm/i915/lnl+/tc: Fix handling of an enabled/disconnected dp-alt sink

["Kahola, Mika" <mika.kahola@intel.com>]

> -----Original Message-----
> From: Intel-xe <intel-xe-bounces@lists.freedesktop.org> On Behalf Of Imre Deak
> Sent: Tuesday, 5 August 2025 10.37
> To: intel-gfx@lists.freedesktop.org; intel-xe@lists.freedesktop.org
> Cc: stable@vger.kernel.org; Lin, Charlton <charlton.lin@intel.com>; Almahallawy, Khaled <khaled.almahallawy@intel.com>
> Subject: [PATCH 01/19] drm/i915/lnl+/tc: Fix handling of an enabled/disconnected dp-alt sink
> 
> The TypeC PHY HW readout during driver loading and system resume determines which TypeC mode the PHY is in (legacy/DP-
> alt/TBT-alt) and whether the PHY is connected, based on the PHY's Owned and Ready flags.
> For the PHY to be in DP-alt or legacy mode and for the PHY to be in the connected state in these modes, both the Owned (set by
> the BIOS/driver) and the Ready (set by the HW) flags should be set.
> 
> On ICL-MTL the HW kept the PHY's Ready flag set after the driver connected the PHY by acquiring the PHY ownership (by setting
> the Owned flag), until the driver disconnected the PHY by releasing the PHY ownership (by clearing the Owned flag). On LNL+ this
> has changed, in that the HW clears the Ready flag as soon as the sink gets disconnected, even if the PHY ownership was acquired
> already and hence the PHY is being used by the display.
> 
> When inheriting the HW state from BIOS for a PHY connected in DP-alt mode on which the sink got disconnected - i.e. in a case
> where the sink was connected while BIOS/GOP was running and so the sink got enabled connecting the PHY, but the user
> disconnected the sink by the time the driver loaded - the PHY Owned but not Ready state must be accounted for on LNL+
> according to the above. Do that by assuming on LNL+ that the PHY is connected in DP-alt mode whenever the PHY Owned flag is
> set, regardless of the PHY Ready flag.
> 
> This fixes a problem on LNL+, where the PHY TypeC mode / connected state was detected incorrectly for a DP-alt sink, which got
> connected and then disconnected by the user in the above way.
> 
> Cc: stable@vger.kernel.org # v6.8+
> Reported-by: Charlton Lin <charlton.lin@intel.com>
> Tested-by: Khaled Almahallawy <khaled.almahallawy@intel.com>

Reviewed-by: Mika Kahola <mika.kahola@intel.com>

> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_tc.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> index 3bc57579fe53e..73a08bd84a70a 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.c
> +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> @@ -1226,14 +1226,18 @@ static void tc_phy_get_hw_state(struct intel_tc_port *tc)
>  	tc->phy_ops->get_hw_state(tc);
>  }
> 
> -static bool tc_phy_is_ready_and_owned(struct intel_tc_port *tc,
> -				      bool phy_is_ready, bool phy_is_owned)
> +static bool tc_phy_in_legacy_or_dp_alt_mode(struct intel_tc_port *tc,
> +					    bool phy_is_ready, bool phy_is_owned)
>  {
>  	struct intel_display *display = to_intel_display(tc->dig_port);
> 
> -	drm_WARN_ON(display->drm, phy_is_owned && !phy_is_ready);
> +	if (DISPLAY_VER(display) < 20) {
> +		drm_WARN_ON(display->drm, phy_is_owned && !phy_is_ready);
> 
> -	return phy_is_ready && phy_is_owned;
> +		return phy_is_ready && phy_is_owned;
> +	} else {
> +		return phy_is_owned;
> +	}
>  }
> 
>  static bool tc_phy_is_connected(struct intel_tc_port *tc, @@ -1244,7 +1248,7 @@ static bool tc_phy_is_connected(struct
> intel_tc_port *tc,
>  	bool phy_is_owned = tc_phy_is_owned(tc);
>  	bool is_connected;
> 
> -	if (tc_phy_is_ready_and_owned(tc, phy_is_ready, phy_is_owned))
> +	if (tc_phy_in_legacy_or_dp_alt_mode(tc, phy_is_ready, phy_is_owned))
>  		is_connected = port_pll_type == ICL_PORT_DPLL_MG_PHY;
>  	else
>  		is_connected = port_pll_type == ICL_PORT_DPLL_DEFAULT; @@ -1352,7 +1356,7 @@
> tc_phy_get_current_mode(struct intel_tc_port *tc)
>  	phy_is_ready = tc_phy_is_ready(tc);
>  	phy_is_owned = tc_phy_is_owned(tc);
> 
> -	if (!tc_phy_is_ready_and_owned(tc, phy_is_ready, phy_is_owned)) {
> +	if (!tc_phy_in_legacy_or_dp_alt_mode(tc, phy_is_ready, phy_is_owned))
> +{
>  		mode = get_tc_mode_in_phy_not_owned_state(tc, live_mode);
>  	} else {
>  		drm_WARN_ON(display->drm, live_mode == TC_PORT_TBT_ALT);
> --
> 2.49.1