Re: [PATCH v3 11/23] drm/i915: Handle the TCCOLD power-down event

Souza, Jose
2019-06-26T22:12:53Z

On Wed, 2019-06-26 at 21:04 +0300, Imre Deak wrote:
> Based on a recent BSpec update (Index/21750) we must handle the
> TCCOLD
> event associated with the DP-alt mode. We can detect this event by
> reading an invalid all-1s value from FIA registers.
>
> After detecting TCCOLD we will:
> - fall back to TBT-alt mode when attempting to switch to DP-alt mode
> - conclude that nothing is connected during live status detection
> - WARN when already in unsafe mode, since then TCCOLD is unexpected
>
> v2:
> - Use DRM_DEBUG_KMS instead of DRM_DEBUG_DRIVER. (José)
> v3:
> - Use 0xffffffff instead of -1 as invalid FIA reg value.
> (José, Ville)
> - Check for TCCOLD in icl_tc_phy_status_complete() too. (Ville)
>
> Cc: José Roberto de Souza <jose.souza@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
> drivers/gpu/drm/i915/display/intel_tc.c | 33 ++++++++++++++++++++++-
> --
> 1 file changed, 29 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c
> b/drivers/gpu/drm/i915/display/intel_tc.c
> index 4243db6d25a7..96855250a5be 100644
> --- a/drivers/gpu/drm/i915/display/intel_tc.c
> +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> @@ -29,6 +29,8 @@ u32 intel_tc_port_get_lane_mask(struct
> intel_digital_port *dig_port)
>
> lane_mask = I915_READ(PORT_TX_DFLEXDPSP);
>
> + WARN_ON(lane_mask == 0xffffffff);

nit: Maybe define it?

#define FIA_TCCOLD_VALUE 0xffffffff

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

> +
> return (lane_mask & DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
> DP_LANE_ASSIGNMENT_SHIFT(tc_port);
> }
> @@ -92,6 +94,12 @@ static u32 tc_port_live_status_mask(struct
> intel_digital_port *dig_port)
>
> val = I915_READ(PORT_TX_DFLEXDPSP);
>
> + if (val == 0xffffffff) {
> + DRM_DEBUG_KMS("Port %s: PHY in TCCOLD, nothing
> connected\n",
> + dig_port->tc_port_name);
> + return mask;
> + }
> +
> if (val & TC_LIVE_STATE_TBT(tc_port))
> mask |= BIT(TC_PORT_TBT_ALT);
> if (val & TC_LIVE_STATE_TC(tc_port))
> @@ -111,12 +119,19 @@ static bool icl_tc_phy_status_complete(struct
> intel_digital_port *dig_port)
> {
> struct drm_i915_private *dev_priv = to_i915(dig_port-
> >base.base.dev);
> enum tc_port tc_port = intel_port_to_tc(dev_priv, dig_port-
> >base.port);
> + u32 val;
>
> - return I915_READ(PORT_TX_DFLEXDPPMS) &
> - DP_PHY_MODE_STATUS_COMPLETED(tc_port);
> + val = I915_READ(PORT_TX_DFLEXDPPMS);
> + if (val == 0xffffffff) {
> + DRM_DEBUG_KMS("Port %s: PHY in TCCOLD, assuming not
> complete\n",
> + dig_port->tc_port_name);
> + return false;
> + }
> +
> + return val & DP_PHY_MODE_STATUS_COMPLETED(tc_port);
> }
>
> -static void icl_tc_phy_set_safe_mode(struct intel_digital_port
> *dig_port,
> +static bool icl_tc_phy_set_safe_mode(struct intel_digital_port
> *dig_port,
> bool enable)
> {
> struct drm_i915_private *dev_priv = to_i915(dig_port-
> >base.base.dev);
> @@ -124,6 +139,13 @@ static void icl_tc_phy_set_safe_mode(struct
> intel_digital_port *dig_port,
> u32 val;
>
> val = I915_READ(PORT_TX_DFLEXDPCSSS);
> + if (val == 0xffffffff) {
> + DRM_DEBUG_KMS("Port %s: PHY in TCCOLD, can't set safe-
> mode to %s\n",
> + dig_port->tc_port_name,
> + enableddisabled(enable));
> +
> + return false;
> + }
>
> val &= ~DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
> if (!enable)
> @@ -134,6 +156,8 @@ static void icl_tc_phy_set_safe_mode(struct
> intel_digital_port *dig_port,
> if (enable && wait_for(!icl_tc_phy_status_complete(dig_port),
> 10))
> DRM_DEBUG_KMS("Port %s: PHY complete clear timed
> out\n",
> dig_port->tc_port_name);
> +
> + return true;
> }
>
> /*
> @@ -172,7 +196,8 @@ static bool icl_tc_phy_connect(struct
> intel_digital_port *dig_port)
> return false;
> }
>
> - icl_tc_phy_set_safe_mode(dig_port, false);
> + if (!icl_tc_phy_set_safe_mode(dig_port, false))
> + return false;
>
> if (dig_port->tc_mode == TC_PORT_LEGACY)
> return true;