[Bug 108924] [CI][BAT] igt@* - dmesg-warn / dmesg-fail - Missing case (intel_dig_port->tc_type == 0)

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108924

--- Comment #2 from Imre Deak <imre.deak at intel.com> ---
This is similar to
https://bugs.freedesktop.org/show_bug.cgi?id=108070

HPD arriving at the wrong moment while we are trying to do a modeset. I think
the solution for both issues will be to keep the port switched to TypeC native
mode according to the patch below. Before going with such a change though we
would need (a) confirmation from HW people that it's safe to do this and (b) a
new flag in VBT that marks the port as TypeC native (vs. being a TypeC USB
alternate/Thunderbolt DP port). The VBT flag would allow us to switch to native
mode right after driver loading, eliminating problems with other use-cases (DP
AUX reading from userspace, modesetting on a port without a sink being
connected). I have opened company internal tickets to track both (a) and (b)
issues, once those are resolved somehow I will follow up here.

commit 1d4ea665f65445817220a7956bf8bca3bd8686e2
Author: Imre Deak <imre.deak at intel.com>
Date:   Fri Nov 30 23:01:56 2018 +0200

    drm/i915/icl: Remain in legacy mode after TC port disconnect IRQ

    Signed-off-by: Imre Deak <imre.deak at intel.com>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 70ae3d57316b..41f9883240cd 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4948,6 +4948,12 @@ static void icl_tc_phy_disconnect(struct
drm_i915_private *dev_priv,
        if (dig_port->tc_type == TC_PORT_UNKNOWN)
                return;

+       if (dig_port->tc_type == TC_PORT_LEGACY) {
+               DRM_DEBUG_DRIVER("Keep TC port %c in legacy mode after
disconnect\n",
+                                port_name(dig_port->base.port));
+               return;
+       }
+
        /*
         * TBT disconnection flow is read the live status, what was done in
         * caller.

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