On Wed, Aug 01, 2018 at 10:34:41AM -0700, Paulo Zanoni wrote:
> Unlike the other ports, TC ports are not available to use as soon as
> we get a hotplug. The TC PHYs can be shared between multiple
> controllers: display, USB, etc. As a result, handshaking through FIA
> is required around connect and disconnect to cleanly transfer
> ownership with the controller and set the type-C power state.
>
> This patch implements the flow sequences described by our
> specification. We opt to grab ownership of the ports as soon as we get
> the hotplugs in order to simplify the interactions and avoid surprises
> in the user space side. We may consider changing this in the future,
> once we improve our testing capabilities on this area.
>
> v2:
> * This unifies the DP and HDMI patches so we can discuss everything
> at once so people looking at random single patches can actually
> understand the direction.
> * I found out the spec was updated a while ago. There's a small
> difference in the connect flow and the patch was updated for that.
> * Our spec also now gives a good explanation on what is really
> happening. As a result, comments were added.
> * Add some more comments as requested by Rodrigo (Rodrigo).
> v3:
> * Downgrade a DRM_ERROR that shouldn't ever happen but we can't act
> on in case it does (Chris).
>
> BSpec: 21750, 4250.
> Cc: Animesh Manna <animesh.manna@xxxxxxxxx>
> Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
sorry for taking so long...
thanks for the doc and all other changes.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_reg.h | 6 +++
> drivers/gpu/drm/i915/intel_dp.c | 110 +++++++++++++++++++++++++++++++++++++-
> drivers/gpu/drm/i915/intel_hdmi.c | 11 ++--
> 3 files changed, 123 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 1da1c7743785..a5f4dfe9ebdf 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -10750,4 +10750,10 @@ enum skl_power_gate {
> #define DP_LANE_ASSIGNMENT_MASK(tc_port) (0xf << ((tc_port) * 8))
> #define DP_LANE_ASSIGNMENT(tc_port, x) ((x) << ((tc_port) * 8))
>
> +#define PORT_TX_DFLEXDPPMS _MMIO(0x163890)
> +#define DP_PHY_MODE_STATUS_COMPLETED(tc_port) (1 << (tc_port))
> +
> +#define PORT_TX_DFLEXDPCSSS _MMIO(0x163894)
> +#define DP_PHY_MODE_STATUS_NOT_SAFE(tc_port) (1 << (tc_port))
> +
> #endif /* _I915_REG_H_ */
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index fec21aa3db93..86eded613456 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -4818,6 +4818,104 @@ static void icl_update_tc_port_type(struct drm_i915_private *dev_priv,
> type_str);
> }
>
> +/*
> + * This function implements the first part of the Connect Flow described by our
> + * specification, Gen11 TypeC Programming chapter. The rest of the flow (reading
> + * lanes, EDID, etc) is done as needed in the typical places.
> + *
> + * Unlike the other ports, type-C ports are not available to use as soon as we
> + * get a hotplug. The type-C PHYs can be shared between multiple controllers:
> + * display, USB, etc. As a result, handshaking through FIA is required around
> + * connect and disconnect to cleanly transfer ownership with the controller and
> + * set the type-C power state.
> + *
> + * We could opt to only do the connect flow when we actually try to use the AUX
> + * channels or do a modeset, then immediately run the disconnect flow after
> + * usage, but there are some implications on this for a dynamic environment:
> + * things may go away or change behind our backs. So for now our driver is
> + * always trying to acquire ownership of the controller as soon as it gets an
> + * interrupt (or polls state and sees a port is connected) and only gives it
> + * back when it sees a disconnect. Implementation of a more fine-grained model
> + * will require a lot of coordination with user space and thorough testing for
> + * the extra possible cases.
> + */
> +static bool icl_tc_phy_connect(struct drm_i915_private *dev_priv,
> + struct intel_digital_port *dig_port)
> +{
> + enum tc_port tc_port = intel_port_to_tc(dev_priv, dig_port->base.port);
> + u32 val;
> +
> + if (dig_port->tc_type != TC_PORT_LEGACY &&
> + dig_port->tc_type != TC_PORT_TYPEC)
> + return true;
> +
> + val = I915_READ(PORT_TX_DFLEXDPPMS);
> + if (!(val & DP_PHY_MODE_STATUS_COMPLETED(tc_port))) {
> + DRM_DEBUG_KMS("DP PHY for TC port %d not ready\n", tc_port);
> + return false;
> + }
> +
> + /*
> + * This function may be called many times in a row without an HPD event
> + * in between, so try to avoid the write when we can.
> + */
> + val = I915_READ(PORT_TX_DFLEXDPCSSS);
> + if (!(val & DP_PHY_MODE_STATUS_NOT_SAFE(tc_port))) {
> + val |= DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
> + I915_WRITE(PORT_TX_DFLEXDPCSSS, val);
> + }
> +
> + /*
> + * Now we have to re-check the live state, in case the port recently
> + * became disconnected. Not necessary for legacy mode.
> + */
> + if (dig_port->tc_type == TC_PORT_TYPEC &&
> + !(I915_READ(PORT_TX_DFLEXDPSP) & TC_LIVE_STATE_TC(tc_port))) {
> + DRM_DEBUG_KMS("TC PHY %d sudden disconnect.\n", tc_port);
> + val = I915_READ(PORT_TX_DFLEXDPCSSS);
> + val &= ~DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
> + I915_WRITE(PORT_TX_DFLEXDPCSSS, val);
> + return false;
> + }
> +
> + return true;
> +}
> +
> +/*
> + * See the comment at the connect function. This implements the Disconnect
> + * Flow.
> + */
> +static void icl_tc_phy_disconnect(struct drm_i915_private *dev_priv,
> + struct intel_digital_port *dig_port)
> +{
> + enum tc_port tc_port = intel_port_to_tc(dev_priv, dig_port->base.port);
> + u32 val;
> +
> + if (dig_port->tc_type != TC_PORT_LEGACY &&
> + dig_port->tc_type != TC_PORT_TYPEC)
> + return;
> +
> + /*
> + * This function may be called many times in a row without an HPD event
> + * in between, so try to avoid the write when we can.
> + */
> + val = I915_READ(PORT_TX_DFLEXDPCSSS);
> + if (val & DP_PHY_MODE_STATUS_NOT_SAFE(tc_port)) {
> + val &= ~DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
> + I915_WRITE(PORT_TX_DFLEXDPCSSS, val);
> + }
> +}
> +
> +/*
> + * 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
> + * icl_tc_phy_connect(). So in our driver instead of adding the additional
> + * concept of "usable" and make everything check for "connected and usable" we
> + * define a port as "connected" when it is not only connected, but also when it
> + * is usable by the rest of the driver. That maintains the old assumption that
> + * connected ports are usable, and avoids exposing to the users objects they
> + * can't really use.
> + */
> static bool icl_tc_port_connected(struct drm_i915_private *dev_priv,
> struct intel_digital_port *intel_dig_port)
> {
> @@ -4836,12 +4934,17 @@ static bool icl_tc_port_connected(struct drm_i915_private *dev_priv,
> is_typec = dpsp & TC_LIVE_STATE_TC(tc_port);
> is_tbt = dpsp & TC_LIVE_STATE_TBT(tc_port);
>
> - if (!is_legacy && !is_typec && !is_tbt)
> + if (!is_legacy && !is_typec && !is_tbt) {
> + icl_tc_phy_disconnect(dev_priv, intel_dig_port);
> return false;
> + }
>
> icl_update_tc_port_type(dev_priv, intel_dig_port, is_legacy, is_typec,
> is_tbt);
>
> + if (!icl_tc_phy_connect(dev_priv, intel_dig_port))
> + return false;
> +
> return true;
> }
>
> @@ -4869,6 +4972,11 @@ static bool icl_digital_port_connected(struct intel_encoder *encoder)
> * intel_digital_port_connected - is the specified port connected?
> * @encoder: intel_encoder
> *
> + * In cases where there's a connector physically connected but it can't be used
> + * by our hardware we also return false, since the rest of the driver should
> + * pretty much treat the port as disconnected. This is relevant for type-C
> + * (starting on ICL) where there's ownership involved.
> + *
> * Return %true if port is connected, %false otherwise.
> */
> bool intel_digital_port_connected(struct intel_encoder *encoder)
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index 8363fbd18ee8..548199e59b6c 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1905,21 +1905,26 @@ intel_hdmi_set_edid(struct drm_connector *connector)
> static enum drm_connector_status
> intel_hdmi_detect(struct drm_connector *connector, bool force)
> {
> - enum drm_connector_status status;
> + enum drm_connector_status status = connector_status_disconnected;
> struct drm_i915_private *dev_priv = to_i915(connector->dev);
> + struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
> + struct intel_encoder *encoder = &hdmi_to_dig_port(intel_hdmi)->base;
>
> DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
> connector->base.id, connector->name);
>
> intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
>
> + if (IS_ICELAKE(dev_priv) &&
> + !intel_digital_port_connected(encoder))
> + goto out;
> +
> intel_hdmi_unset_edid(connector);
>
> if (intel_hdmi_set_edid(connector))
> status = connector_status_connected;
> - else
> - status = connector_status_disconnected;
>
> +out:
> intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
>
> return status;
> --
> 2.14.4
>
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