If we fail to commit an entity, we need to restore the UVC_CTRL_DATA_BACKUP for the other uncommitted entities. Otherwise the control cache and the device would be out of sync.
Cc: stable@kernel.org Fixes: b4012002f3a3 ("[media] uvcvideo: Add support for control events") Reported-by: Hans de Goede hdegoede@redhat.com Closes: https://lore.kernel.org/linux-media/fe845e04-9fde-46ee-9763-a6f00867929a@red... Signed-off-by: Ricardo Ribalda ribalda@chromium.org Message-ID: 20250224-uvc-data-backup-v2-3-de993ed9823b@chromium.org Signed-off-by: Hans de Goede hdegoede@redhat.com Signed-off-by: Hans Verkuil hverkuil@xs4all.nl (cherry picked from commit a70705d3c020d0d5c3ab6a5cc93e011ac35e7d48) Signed-off-by: Ricardo Ribalda ribalda@chromium.org --- drivers/media/usb/uvc/uvc_ctrl.c | 34 +++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c index c70d9c24c6fb..957d620ad671 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -1848,7 +1848,7 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev, unsigned int processed_ctrls = 0; struct uvc_control *ctrl; unsigned int i; - int ret; + int ret = 0;
if (entity == NULL) return 0; @@ -1877,8 +1877,6 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev, dev->intfnum, ctrl->info.selector, uvc_ctrl_data(ctrl, UVC_CTRL_DATA_CURRENT), ctrl->info.size); - else - ret = 0;
if (!ret) processed_ctrls++; @@ -1890,17 +1888,24 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
ctrl->dirty = 0;
- if (ret < 0) { + if (ret < 0 && !rollback) { if (err_ctrl) *err_ctrl = ctrl; - return ret; + /* + * If we fail to set a control, we need to rollback + * the next ones. + */ + rollback = 1; }
- if (!rollback && handle && + if (!rollback && handle && !ret && ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS) uvc_ctrl_set_handle(handle, ctrl, handle); }
+ if (ret) + return ret; + return processed_ctrls; }
@@ -1931,7 +1936,8 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback, struct uvc_video_chain *chain = handle->chain; struct uvc_control *err_ctrl; struct uvc_entity *entity; - int ret = 0; + int ret_out = 0; + int ret;
/* Find the control. */ list_for_each_entry(entity, &chain->entities, chain) { @@ -1942,17 +1948,23 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback, ctrls->error_idx = uvc_ctrl_find_ctrl_idx(entity, ctrls, err_ctrl); - goto done; + /* + * When we fail to commit an entity, we need to + * restore the UVC_CTRL_DATA_BACKUP for all the + * controls in the other entities, otherwise our cache + * and the hardware will be out of sync. + */ + rollback = 1; + + ret_out = ret; } else if (ret > 0 && !rollback) { uvc_ctrl_send_events(handle, entity, ctrls->controls, ctrls->count); } }
- ret = 0; -done: mutex_unlock(&chain->ctrl_mutex); - return ret; + return ret_out; }
int uvc_ctrl_get(struct uvc_video_chain *chain,