The patch below does not apply to the 6.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.15.y git checkout FETCH_HEAD git cherry-pick -x a70705d3c020d0d5c3ab6a5cc93e011ac35e7d48 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025062014-prideful-exemplary-1838@gregkh' --subject-prefix 'PATCH 6.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a70705d3c020d0d5c3ab6a5cc93e011ac35e7d48 Mon Sep 17 00:00:00 2001 From: Ricardo Ribalda ribalda@chromium.org Date: Mon, 24 Feb 2025 10:34:55 +0000 Subject: [PATCH] media: uvcvideo: Rollback non processed entities on error

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

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c index 636ce1eb2a6b..44b6513c5264 100644 --- a/drivers/media/usb/uvc/uvc_ctrl.c +++ b/drivers/media/usb/uvc/uvc_ctrl.c @@ -2119,7 +2119,7 @@ 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; @@ -2148,8 +2148,6 @@ 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++; @@ -2165,13 +2163,20 @@ static int uvc_ctrl_commit_entity(struct uvc_device *dev, ctrl->info.flags & UVC_CTRL_FLAG_ASYNCHRONOUS) ret = uvc_ctrl_set_handle(handle, ctrl, handle);

- 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 (ret) + return ret; + return processed_ctrls; }

@@ -2202,7 +2207,8 @@ 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) { @@ -2213,17 +2219,23 @@ 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; }

static int uvc_mapping_get_xctrl_compound(struct uvc_video_chain *chain,