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drm/probe-helper: Introduce .force_ctx() connector callback

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The .force() connector callback is invoked by
drm_helper_probe_single_connector_modes() while the modeset acquire
context it created is live, but the hook signature provides no way to
pass it down, e.g. to support implementations needing to lock further
objects.

Add a .force_ctx() variant to drm_connector_helper_funcs, taking the
acquire context and returning an error code, so that -EDEADLK propagates
into the existing retry path.  When provided, it takes precedence over
drm_connector_funcs' .force(), which is kept for existing users.

This is a prerequisite for SCDC status synchronization in the HDMI
connector framework.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patch.msgid.link/20260901-dw-hdmi-qp-scramb-v11-6-bc12954a0688@collabora.com
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
This commit is contained in:
Cristian Ciocaltea 2026-09-01 21:50:30 +03:00
parent cc6d8b2f87
commit 9d1e2ae719
3 changed files with 48 additions and 1 deletions
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15
drivers/gpu/drm/drm_probe_helper.c
View File

@ -559,6 +559,7 @@ static int __drm_helper_update_and_validate(struct drm_connector *connector,
int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
uint32_t maxX, uint32_t maxY)
{
const struct drm_connector_helper_funcs *funcs = connector->helper_private;
struct drm_device *dev = connector->dev;
struct drm_display_mode *mode;
int count = 0, ret;
@ -592,8 +593,20 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
connector->status = connector_status_connected;
else
connector->status = connector_status_disconnected;
if (connector->funcs->force)
if (funcs && funcs->force_ctx) {
ret = funcs->force_ctx(connector, &ctx);
if (ret == -EDEADLK) {
connector->status = old_status;
drm_modeset_backoff(&ctx);
goto retry;
} else if (ret < 0) {
drm_dbg_kms(dev, "[CONNECTOR:%d:%s] force_ctx failed: %d\n",
connector->base.id, connector->name, ret);
}
} else if (connector->funcs->force) {
connector->funcs->force(connector);
}
} else {
ret = drm_helper_probe_detect(connector, &ctx, true);

6
include/drm/drm_connector.h
View File

@ -1670,6 +1670,12 @@ struct drm_connector_funcs {
* the sysfs interfaces or on the kernel cmdline. In that case the
* @detect callback isn't called.
*
* New drivers should implement
* &drm_connector_helper_funcs.force_ctx instead, which gets passed
* the modeset acquire context and thus allows taking additional
* locks. It takes precedence over this callback when both are
* implemented.
*
* FIXME:
*
* Note that this hook is only called by the probe helper. It's not in

28
include/drm/drm_modeset_helper_vtables.h
View File

@ -935,6 +935,34 @@ struct drm_connector_helper_funcs {
struct drm_modeset_acquire_ctx *ctx,
bool force);
/**
* @force_ctx:
*
* This function is called to update internal encoder state when the
* connector is forced to a certain state by userspace, either through
* the sysfs interfaces or on the kernel cmdline. In that case the
* @detect_ctx callback isn't called.
*
* This is the atomic version of &drm_connector_funcs.force. When
* both are implemented, this one takes precedence and
* &drm_connector_funcs.force is not called.
*
* To avoid races against concurrent connector state updates, the
* helper libraries always call this with ctx set to a valid context,
* and &drm_mode_config.connection_mutex will always be locked with
* the ctx parameter set to this ctx. This allows taking additional
* locks as required.
*
* RETURNS:
*
* Zero on success, or a negative error code otherwise. This includes
* -EDEADLK when a lock acquisition needs to be restarted, in which
* case the helpers take care of backing off and calling this function
* again.
*/
int (*force_ctx)(struct drm_connector *connector,
struct drm_modeset_acquire_ctx *ctx);
/**
* @mode_valid:
*