On Sun, Feb 26, 2023 at 09:04:16PM -0500, Sasha Levin wrote:
From: Bjorn Andersson quic_bjorande@quicinc.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@quicinc.com Reviewed-by: Kuogee Hsieh quic_khsieh@quicinc.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@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org
This is not a bug fix and should not be backported.
Johan