"detect" should not be called and its return value shall not be used when a
connector is forced as hinted in the commit d50ba256b5f1 ("drm/kms: start
adding command line interface using fb.") and the commit 6fe14acd496e
("drm: Document drm_connector_funcs"). One negative side effect of doing
this is observed on the RCar3 SoCs which use the dw-hdmi driver. It
continues executing drm_helper_hpd_irq_event even if its connector is
forced to ON. As consequence drm_helper_hpd_irq_event calls "detect" so the
connector status is updated to "disconnected":
[ 420.201527] [drm:drm_helper_hpd_irq_event] [CONNECTOR:76:HDMI-A-1] status updated from connected to disconnected
This status is corrected by drm_helper_probe_single_connector_modes shortly
after this because this function checks if a connector is forced:
[ 420.218703] [drm:drm_helper_probe_single_connector_modes] [CONNECTOR:76:HDMI-A-1] status updated from disconnected to connected
To avoid similar issues this commit adapts functions which call "detect"
so they check if a connector is forced and return the correct status.
Fixes: 949f08862d66 ("drm: Make the connector .detect() callback optional")
Signed-off-by: Michael Rodin <mrodin@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_probe_helper.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index bb427c5a4f1f..1691047d0472 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -289,7 +289,12 @@ drm_helper_probe_detect_ctx(struct drm_connector *connector, bool force)
retry:
ret = drm_modeset_lock(&connector->dev->mode_config.connection_mutex, &ctx);
if (!ret) {
- if (funcs->detect_ctx)
+ if (connector->force == DRM_FORCE_ON ||
+ connector->force == DRM_FORCE_ON_DIGITAL)
+ ret = connector_status_connected;
+ else if (connector->force == DRM_FORCE_OFF)
+ ret = connector_status_disconnected;
+ else if (funcs->detect_ctx)
ret = funcs->detect_ctx(connector, &ctx, force);
else if (connector->funcs->detect)
ret = connector->funcs->detect(connector, force);
@@ -340,7 +345,14 @@ drm_helper_probe_detect(struct drm_connector *connector,
if (ret)
return ret;
- if (funcs->detect_ctx)
+ if (connector->force == DRM_FORCE_ON ||
+ connector->force == DRM_FORCE_ON_DIGITAL)
+ ret = connector_status_connected;
+ else if (connector->force == DRM_FORCE_OFF)
+ ret = connector_status_disconnected;
+ else if (funcs->detect_ctx)
+ ret = funcs->detect_ctx(connector, ctx, force);
+ else if (funcs->detect_ctx)
ret = funcs->detect_ctx(connector, ctx, force);
else if (connector->funcs->detect)
ret = connector->funcs->detect(connector, force);
--
2.25.1
