From: Philip Chen <philipchen@chromium.org> stable inclusion from stable-v5.10.87 commit 990fd815ec88487f6191bbf5ae06919ced82902d bugzilla: 186049 https://gitee.com/openeuler/kernel/issues/I4QVYL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit cd92cc187c053ab010a1570e2d61d68394a5c725 ] If "data_lanes" property of the dsi output endpoint is missing in the DT, num_data_lanes would be 0 by default, which could cause dsi_host_attach() to fail if dsi->lanes is set to a non-zero value by the bridge driver. According to the binding document of msm dsi controller, the input/output endpoint of the controller is expected to have 4 lanes. So let's set num_data_lanes to 4 by default. Signed-off-by: Philip Chen <philipchen@chromium.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Stephen Boyd <swboyd@chromium.org> Link: https://lore.kernel.org/r/20211030100812.1.I6cd9af36b723fed277d34539d3b2ba4c... Signed-off-by: Rob Clark <robdclark@chromium.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- drivers/gpu/drm/msm/dsi/dsi_host.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index 96b5dcf8e454..64454a63bbac 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -1692,6 +1692,8 @@ static int dsi_host_parse_lane_data(struct msm_dsi_host *msm_host, if (!prop) { DRM_DEV_DEBUG(dev, "failed to find data lane mapping, using default\n"); + /* Set the number of date lanes to 4 by default. */ + msm_host->num_data_lanes = 4; return 0; } -- 2.20.1