kernel/drivers/usb/gadget/function/uvc_video.c, branch linux-rolling-stable

usb: gadget: uvc: fix interval_duration calculation

2026-03-19T15:15:05Z

commit 56135c0c60b07729401af9d329fa9c0eded845a6 upstream. To correctly convert bInterval as interval_duration: interval_duration = 2^(bInterval-1) * frame_interval Current code uses a wrong left shift operand, computing 2^bInterval instead of 2^(bInterval-1). Fixes: 010dc57cb516 ("usb: gadget: uvc: fix interval_duration calculation") Cc: stable Signed-off-by: Junzhong Pan Reviewed-by: Xu Yang Link: https://patch.msgid.link/20260306-fix-uvc-interval-v1-1-9a2df6859859@linux.spacemit.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: return error from uvcg_queue_init()

2026-01-14T15:03:18Z

uvcg_queue_init() may fail, but its return value is currently ignored. Propagate the error code from uvcg_queue_init() to correctly report initialization failures. Signed-off-by: Xu Yang Link: https://patch.msgid.link/20260113-uvc-gadget-fix-patch-v2-3-62950ef5bcb5@nxp.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: fix interval_duration calculation

2026-01-14T15:03:17Z

According to USB specification: For full-/high-speed isochronous endpoints, the bInterval value is used as the exponent for a 2^(bInterval-1) value. To correctly convert bInterval as interval_duration: interval_duration = 2^(bInterval-1) * frame_interval Because the unit of video->interval is 100ns, add a comment info to make it clear. Fixes: 48dbe731171e ("usb: gadget: uvc: set req_size and n_requests based on the frame interval") Cc: stable@vger.kernel.org Reviewed-by: Frank Li Signed-off-by: Xu Yang Link: https://patch.msgid.link/20260113-uvc-gadget-fix-patch-v2-2-62950ef5bcb5@nxp.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: fix req_payload_size calculation

2026-01-14T15:03:17Z

Current req_payload_size calculation has 2 issue: (1) When the first time calculate req_payload_size for all the buffers, reqs_per_frame = 0 will be the divisor of DIV_ROUND_UP(). So the result is undefined. This happens because VIDIOC_STREAMON is always executed after VIDIOC_QBUF. So video->reqs_per_frame will be 0 until VIDIOC_STREAMON is run. (2) The buf->req_payload_size may be bigger than max_req_size. Take YUYV pixel format as example: If bInterval = 1, video->interval = 666666, high-speed: video->reqs_per_frame = 666666 / 1250 = 534 720p: buf->req_payload_size = 1843200 / 534 = 3452 1080p: buf->req_payload_size = 4147200 / 534 = 7766 Based on such req_payload_size, the controller can't run normally. To fix above issue, assign max_req_size to buf->req_payload_size when video->reqs_per_frame = 0. And limit buf->req_payload_size to video->req_size if it's large than video->req_size. Since max_req_size is used at many place, add it to struct uvc_video and set the value once endpoint is enabled. Fixes: 98ad03291560 ("usb: gadget: uvc: set req_length based on payload by nreqs instead of req_size") Cc: stable@vger.kernel.org Reviewed-by: Frank Li Signed-off-by: Xu Yang Link: https://patch.msgid.link/20260113-uvc-gadget-fix-patch-v2-1-62950ef5bcb5@nxp.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: Fix unstarted kthread worker

2025-02-14T08:26:00Z

The behaviour of kthread_create_worker() was recently changed to align with the one of kthread_create(). The kthread worker is created but not awaken by default. This is to allow the use of kthread_affine_preferred() and kthread_bind[_mask]() with kthread workers. In order to keep the old behaviour and wake the kthread up, kthread_run_worker() must be used. All the pre-existing users have been converted, except for UVC that was introduced in the same merge window as the API change. This results in hangs: INFO: task UVCG:82 blocked for more than 491 seconds. Tainted: G T 6.13.0-rc2-00014-gb04e317b5226 #1 task:UVCG state:D stack:0 pid:82 Call Trace: __schedule schedule schedule_preempt_disabled kthread ? kthread_flush_work ret_from_fork ret_from_fork_asm entry_INT80_32 Fix this with converting UVCG kworker to the new API. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202502121025.55bfa801-lkp@intel.com Fixes: f0bbfbd16b3b ("usb: gadget: uvc: rework to enqueue in pump worker from encoded queue") Cc: stable Cc: Michael Grzeschik Signed-off-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20250212135514.30539-1-frederic@kernel.org Signed-off-by: Greg Kroah-Hartman

drivers/usb/gadget: refactor min with min_t

2024-11-13T14:09:50Z

Ensure type safety by using min_t() instead of casted min(). Signed-off-by: Sabyrzhan Tasbolatov Link: https://lore.kernel.org/r/20241112155817.3512577-2-snovitoll@gmail.com Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: add trace of enqueued and completed requests

2024-10-17T06:42:23Z

This patch is adding trace events for each request that is being enqueued into the hw and will be completed. This way it is possible to track the fill status of the gadget hardware and find potential issues. Signed-off-by: Michael Grzeschik Link: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v7-8-e224bb1035f0@pengutronix.de Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: set req_length based on payload by nreqs instead of req_size

2024-10-17T06:42:22Z

Compressed formats generate content depending amount of data that is set in the vb2 buffer by the payload_size. When streaming those formats it is better to scatter that smaller data over all requests. This patch is doing that by introducing the calculated req_payload_size which is updated by each frame. It the uses this amount of data to fill the isoc requests instead of the video->req_size. For uncompressed formats it will not make a difference since the payload size will be equal to the imagesize. Therefore the code will have no effecta as req_payload_size will be equal to req_size. Signed-off-by: Michael Grzeschik Link: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v7-6-e224bb1035f0@pengutronix.de Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: set req_size and n_requests based on the frame interval

2024-10-17T06:42:22Z

This patch is removing the initial imprecise and limited calculation of requests needed to be used from the queue_setup callback. It instead introduces the uvc_video_prep_requests function which is called immediately before the request allocation. With the information of the usb frame interval length it is possible to calculate the number of requests needed during one frame duration. Based on the calculated number of requests and the imagesize we calculate the actual size per request. This calculation has the benefit that the frame data is equally distributed over all allocated requests. When the req_size is not in the range for the actually configured max_req_size configured for the overall bandwidth we fallback to use the max_req_size instead. Since this calculations are only important for isoc transfers we just use max_request_size for bulk and skip it. As video->req_size will be recalculated on every video_enable resetting it to 0 is not necessary anymore. Signed-off-by: Michael Grzeschik Link: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v7-5-e224bb1035f0@pengutronix.de Signed-off-by: Greg Kroah-Hartman

usb: gadget: uvc: add g_parm and s_parm for frame interval

2024-10-17T06:42:22Z

The uvc gadget driver is lacking the information which frame interval was set by the host. We add this information by implementing the g_parm and s_parm callbacks. Signed-off-by: Michael Grzeschik Link: https://lore.kernel.org/r/20240403-uvc_request_length_by_interval-v7-4-e224bb1035f0@pengutronix.de Signed-off-by: Greg Kroah-Hartman