drm/amd/display: workaround for hard hang on HPD on native DP
stable inclusion from stable-5.10.61 commit 2e6cc93e1b8cf3ec2966961c1e98722ee7281023 bugzilla: 177029 https://gitee.com/openeuler/kernel/issues/I4EAXD Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2e6cc93e1b8cf3ec2966961c1e98722ee7281023 -------------------------------- [ Upstream commit c4152b29 ] [Why] HPD disable and enable sequences are not mutually exclusive on Linux. For HPDs that spans over 1s (i.e. HPD low = 1s), part of the disable sequence (specifically, a request to SMU to lower refclk) could come right before the call to PHY enable, causing DMUB to access an unresponsive PHY and thus a hard hang on the system. [How] Disable 48mhz refclk off on native DP. Reviewed-by: NHersen Wu <hersenxs.wu@amd.com> Acked-by: NAurabindo Pillai <aurabindo.pillai@amd.com> Signed-off-by: NQingqing Zhuo <qingqing.zhuo@amd.com> Signed-off-by: NAlex Deucher <alexander.deucher@amd.com> Signed-off-by: NSasha Levin <sashal@kernel.org> Signed-off-by: NChen Jun <chenjun102@huawei.com> Acked-by: NWeilong Chen <chenweilong@huawei.com> Signed-off-by: NChen Jun <chenjun102@huawei.com> Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
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