usb: typec: mux: intel_pmc_mux: Fix DP alternate mode entry

The PMC needs to be notified separately about HPD (hotplug
detected) signal being high after mode entry. There is a bit
"HPD High" in the Alternate Mode Request that the driver
already sets, but that bit is only valid when the
DisplayPort Alternate Mode is directly entered from
disconnected state.

Fixes: 5c4edcdbcd97 ("usb: typec: mux: intel: Fix DP_HPD_LVL bit field")
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Tested-by: Prashant Malani <pmalani@chromium.org>
Link: https://lore.kernel.org/r/20200529131753.15587-1-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
index 962bc69a6a59e4b1f8515731001cb397944010b1..70ddc9d6d49e4636dbeadc41604908fe53f5d8c6 100644 (file)
--- a/drivers/usb/typec/mux/intel_pmc_mux.c
+++ b/drivers/usb/typec/mux/intel_pmc_mux.c
@@ -148,7 +148,8 @@ pmc_usb_mux_dp_hpd(struct pmc_usb_port *port, struct typec_mux_state *state)
        msg[0] = PMC_USB_DP_HPD;
        msg[0] |= port->usb3_port << PMC_USB_MSG_USB3_PORT_SHIFT;
 
-       msg[1] = PMC_USB_DP_HPD_IRQ;
+       if (data->status & DP_STATUS_IRQ_HPD)
+               msg[1] = PMC_USB_DP_HPD_IRQ;
 
        if (data->status & DP_STATUS_HPD_STATE)
                msg[1] |= PMC_USB_DP_HPD_LVL;
@@ -161,6 +162,7 @@ pmc_usb_mux_dp(struct pmc_usb_port *port, struct typec_mux_state *state)
 {
        struct typec_displayport_data *data = state->data;
        struct altmode_req req = { };
+       int ret;
 
        if (data->status & DP_STATUS_IRQ_HPD)
                return pmc_usb_mux_dp_hpd(port, state);
@@ -181,7 +183,14 @@ pmc_usb_mux_dp(struct pmc_usb_port *port, struct typec_mux_state *state)
        if (data->status & DP_STATUS_HPD_STATE)
                req.mode_data |= PMC_USB_ALTMODE_HPD_HIGH;
 
-       return pmc_usb_command(port, (void *)&req, sizeof(req));
+       ret = pmc_usb_command(port, (void *)&req, sizeof(req));
+       if (ret)
+               return ret;
+
+       if (data->status & DP_STATUS_HPD_STATE)
+               return pmc_usb_mux_dp_hpd(port, state);
+
+       return 0;
 }
 
 static int