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 | 42 +++++++++++++++++++++----------- 1 file changed, 28 insertions(+), 14 deletions(-)
diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c index 2dac0eeed55b..c9e5a74e0f0d 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -1577,7 +1577,7 @@ 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; @@ -1605,8 +1605,6 @@ 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++; @@ -1618,14 +1616,22 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev,
ctrl->dirty = 0;
- if (ret < 0) - return ret; - - if (!rollback && handle && + if (!rollback && handle && !ret && ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS) uvc_ctrl_set_handle(handle, ctrl, handle); + + if (ret < 0 && !rollback) { + /* + * If we fail to set a control, we need to rollback + * the next ones. + */ + rollback = 1; + } }
+ if (ret) + return ret; + return processed_ctrls; }
@@ -1635,23 +1641,31 @@ int __uvc_ctrl_commit(struct uvc_fh *handle, int rollback, { struct uvc_video_chain *chain = handle->chain; struct uvc_entity *entity; - int ret = 0; + int ret_out = 0; + int ret;
/* Find the control. */ list_for_each_entry(entity, &chain->entities, chain) { ret = uvc_ctrl_commit_entity(chain->dev, handle, entity, rollback); - if (ret < 0) - goto done; - else if (ret > 0 && !rollback) + if (ret < 0) { + /* + * 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, xctrls, xctrls_count); + } }
- ret = 0; -done: mutex_unlock(&chain->ctrl_mutex); - return ret; + return ret_out; }
int uvc_ctrl_get(struct uvc_video_chain *chain,