Re: [PATCH v2 11/23] drm/i915: Handle the TCCOLD power-down event

Ville Syrjälä
2019-06-25T13:17:38Z

On Thu, Jun 20, 2019 at 05:05:48PM +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)

We don't seem to care about the all 1s in icl_tc_phy_status_complete()
and icl_tc_phy_is_in_safe_mode(). Is that OK?

>
> 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 | 23 +++++++++++++++++++++--
> 1 file changed, 21 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> index a02513814392..fffe4c4a6602 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 == -1);
> +
> return (lane_mask & DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
> DP_LANE_ASSIGNMENT_SHIFT(tc_port);
> }
> @@ -89,6 +91,12 @@ static u32 tc_port_live_status_mask(struct intel_digital_port *dig_port)
>
> val = I915_READ(PORT_TX_DFLEXDPSP);
>
> + if (val == -1) {

Not sure I like this -1 use. I don't think we typically use it elsewhere
in similar context.

> + 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))
> @@ -113,7 +121,7 @@ static bool icl_tc_phy_status_complete(struct intel_digital_port *dig_port)
> 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);
> @@ -122,6 +130,14 @@ static void icl_tc_phy_set_safe_mode(struct intel_digital_port *dig_port,
>
> val = I915_READ(PORT_TX_DFLEXDPCSSS);
>
> + if (val == -1) {
> + 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)
> val |= DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
> @@ -131,6 +147,8 @@ 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;
> }
>
> /*
> @@ -169,7 +187,8 @@ 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;
> --
> 2.17.1

--
Ville Syrjälä
Intel