linux-kernel - [PATCH AUTOSEL 6.1 18/58] drm/msm/dp: Remove INIT

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Date:   Sun, 26 Feb 2023 21:04:16 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Bjorn Andersson <quic_bjorande@...cinc.com>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sasha Levin <sashal@...nel.org>, robdclark@...il.com,
        quic_abhinavk@...cinc.com, airlied@...il.com, daniel@...ll.ch,
        swboyd@...omium.org, johan+linaro@...nel.org,
        quic_sbillaka@...cinc.com, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.1 18/58] drm/msm/dp: Remove INIT_SETUP delay

From: Bjorn Andersson <quic_bjorande@...cinc.com>

[ Upstream commit e17af1c9d861dc177e5b56009bd4f71ace688d97 ]

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>
Reviewed-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/518729/
Link: https://lore.kernel.org/r/20230117172951.2748456-1-quic_bjorande@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 c9d9b384ddd03..85a375d94df56 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1497,7 +1497,7 @@ 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)
-- 
2.39.0