[PATCH 5.17 0575/1126] drm/msm/dp: fix panel bridge attachment

Greg Kroah-Hartman
2022-04-05T09:08:15Z

From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

[ Upstream commit 4d793a02c4967ab14d4ae5e86a51ee02ed78921a ]

In commit 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display
enable and disable") the DP driver received a drm_bridge instance, which
is always attached to the encoder as a root bridge. However it conflicts
with the panel_bridge support for eDP panels. The panel bridge attaches
to the encoder before the "dp" bridge (DP driver's drm_bridge instance
created in msm_dp_bridge_init()) has a chance to do so. Change
panel bridge attachment to come after the "dp" bridge attachment (and to
use it as a previous bridge).

Fixes: 8a3b4c17f863 ("drm/msm/dp: employ bridge mechanism for display enable and disable")
Cc: Kuogee Hsieh <quic_khsieh@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20220211224006.1797846-2-dmitry.baryshkov@linaro.org
[db: fixed commit message according to Stephen's suggestions]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/msm/dp/dp_drm.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_drm.c b/drivers/gpu/drm/msm/dp/dp_drm.c
index d4d360d19eba..26ef41a4c1b6 100644
--- a/drivers/gpu/drm/msm/dp/dp_drm.c
+++ b/drivers/gpu/drm/msm/dp/dp_drm.c
@@ -169,16 +169,6 @@ struct drm_connector *dp_drm_connector_init(struct msm_dp *dp_display)

drm_connector_attach_encoder(connector, dp_display->encoder);

- if (dp_display->panel_bridge) {
- ret = drm_bridge_attach(dp_display->encoder,
- dp_display->panel_bridge, NULL,
- DRM_BRIDGE_ATTACH_NO_CONNECTOR);
- if (ret < 0) {
- DRM_ERROR("failed to attach panel bridge: %d\n", ret);
- return ERR_PTR(ret);
- }
- }
-
return connector;
}

@@ -246,5 +236,16 @@ struct drm_bridge *msm_dp_bridge_init(struct msm_dp *dp_display, struct drm_devi
return ERR_PTR(rc);
}

+ if (dp_display->panel_bridge) {
+ rc = drm_bridge_attach(dp_display->encoder,
+ dp_display->panel_bridge, bridge,
+ DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+ if (rc < 0) {
+ DRM_ERROR("failed to attach panel bridge: %d\n", rc);
+ drm_bridge_remove(bridge);
+ return ERR_PTR(rc);
+ }
+ }
+
return bridge;
}
--
2.34.1