linux-kernel - [PATCH] drm/msm/dp: Remove INIT

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Message-ID: <20230117172951.2748456-1-quic_bjorande@quicinc.com>
Date:   Tue, 17 Jan 2023 09:29:51 -0800
From:   Bjorn Andersson <quic_bjorande@...cinc.com>
To:     Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>,
        Johan Hovold <johan+linaro@...nel.org>,
        Sankeerth Billakanti <quic_sbillaka@...cinc.com>
CC:     Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        "Daniel Vetter" <daniel@...ll.ch>, <linux-arm-msm@...r.kernel.org>,
        <dri-devel@...ts.freedesktop.org>,
        <freedreno@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] drm/msm/dp: Remove INIT_SETUP delay

During initalization of the DisplayPort controller an EV_HPD_INIT_SETUP
event is generated, but with a delay of 100 units. This delay existed to
circumvent bug in the QMP combo PHY driver, where if the DP part was
powered up before USB, the common properties would not be properly
initialized - and USB wouldn't work.

This issue was resolved in the recent refactoring of the QMP driver,
so it's now possible to remove this delay.

While there is still a timing dependency in the current implementation,
test indicates that it's now possible to boot with an external display
on USB Type-C and have the display power up, without disconnecting and
reconnecting the cable.

Signed-off-by: Bjorn Andersson <quic_bjorande@...cinc.com>
---
 drivers/gpu/drm/msm/dp/dp_display.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index db9783ffd5cf..bde1a7ce442f 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1506,7 +1506,7 @@ void msm_dp_irq_postinstall(struct msm_dp *dp_display)
 	dp = container_of(dp_display, struct dp_display_private, dp_display);

 	if (!dp_display->is_edp)
-		dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 100);
+		dp_add_event(dp, EV_HPD_INIT_SETUP, 0, 0);
 }

 bool msm_dp_wide_bus_available(const struct msm_dp *dp_display)
-- 
2.37.3