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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?kMgBdu1oERGLFu3HfUrs5OenogENF2nvDivT8QeSy46zglgPjhwXjGsW8yWN?= =?us-ascii?Q?c5X8IetvzuX0ajIjZIBwAfCq+aiiG0BcvMO/M/piBfqa+SFVvjUCsoOP2TDO?= =?us-ascii?Q?0eSx3d269XZ97hMwBhUcUE816hnDY9A+ayrVy21HKH5QMdQsuv207sLbfZ11?= =?us-ascii?Q?l889AXPES6+pENLLVd/Vw2lOHJDGqkYHa5S9PHJPygRRryittz3jwGLzuv16?= =?us-ascii?Q?asc6ekB64mq3JO8yMQsJhBfnXFGtL3qqfVu2st3mvtx747QkPWW5mLnl3/gW?= =?us-ascii?Q?AZht7VSeelMB5GHRuMsdHnghdLgrgMHklZGqsDYRh+nE86NKvOBMNyds8Nlg?= =?us-ascii?Q?SPL4r0eYVG32QZYO3zED7nK4SJFFAyBtX6yg64x3/bm0Lhs9LY6LF4cVAxxm?= =?us-ascii?Q?93PcHxtd86jaSO1BCMHVqYqtIhqNYUYT+HeX2Ji6HFewrQkq0319u0yailRV?= =?us-ascii?Q?TLxzJs6pu5PriuDBB+nbHEetuQLmlBhvcQiWnqhnk4pd7BvMTI7vBfChQn/F?= =?us-ascii?Q?NmP+TvRcTG7XPX1E8rexn0MktqXpQ3qJVzbDPhSS3Kt+GKPuzMipyBrLIgXH?= =?us-ascii?Q?Q6rGNCpNTbBrXPbOAXz+8O3+QuA7FLFPdjj0XpPI4fzv9ZzF640nhIfye9oo?= =?us-ascii?Q?ekmetghHX8ziHj6VmRTPxmfMtvh0Pq1CQQus0LZkl8ZLnVCE5IuAgR7QFEzY?= =?us-ascii?Q?uaGOWfodyvrIThpXFHIL4lhvMyPoDsvbsF8AtMhPy/HwleHRXWhUrLZGV4cw?= =?us-ascii?Q?V7pOdkim9YVJlVSNxbvDLdiUKvQS+IbLai5JOaORN5UvAZNJbifEE4oPT/wj?= =?us-ascii?Q?kHnzF/5xlDmKV+IrxmTgkS/DG2tb9JLdDDkWK0QAaNfCL5XsNr+4NHk7nX39?= =?us-ascii?Q?cHnQEKr245r1spziHrL+l3lR9GRMq24V7n++SUuwOY0WOYqMjfuTSOYaNFZ/?= =?us-ascii?Q?nsjqqmUalQrlCYyQo5lAOMgDKRtoPw+DlLg6rppcY8MfCHiUjvnrl1hTgcrM?= =?us-ascii?Q?TwlolHgWNPUsjamNM/ALlNTtLBfn4Go3wqp8T212JlPIXlJTDMDyKghkbLAa?= =?us-ascii?Q?mW04gjGW/uKJeU9SzsbxqruiWz1brwmwTmIL6uZ5/IRMyE15TVKZWJ+lJys2?= =?us-ascii?Q?s+/KCP6eSFYPk7X9ZDB6fbzgk+uzP5OOQWBdFchZ/mOSm+8dHpOE2kdlVMVi?= =?us-ascii?Q?FhWrAv6iEn9ebhxj3FBNM+JAgeqK4it9aC54KvVmEVSk/DrN+wKK1EL7e+Ig?= =?us-ascii?Q?1kk/1Vefhu4o9h3+D/RuFPKxg7v0ppl7wK4bHu+qGW1P+0uKMZdTkqezQyNw?= =?us-ascii?Q?JqaW5yiOtbjpasA63Q71PywwlXsQBxWiyxyab29Q5A4+UaTm60mdiwH+8ai4?= =?us-ascii?Q?WwEL17tuRHPjZ81LgzVcdtvW6QjcsrqU2YgZKhOfbDIc5vFxIuZ2RYQOCRMr?= =?us-ascii?Q?COXIeiMOoRbq4/TAbXGGLQPhJgs/DLpd8ax2xIkM8eYR9yo9iWHcPuCwZ6Wc?= =?us-ascii?Q?pNLrDWUeaj0aZRa+dty6yuzznOjDWAFfbG8isgYTGXstyPKGM2LZw/C35T6O?= =?us-ascii?Q?hogdA1S5HegueCQCa+uutNEU7K6ifORetBZweWTUDWg1l/7ZFkLcmUVJO013?= =?us-ascii?Q?HMDD/1L/UYsA51GvAKWoJNmTWGb3ej6BbPc/D820XJoraHLQ7cluyWYS3osS?= =?us-ascii?Q?V6Bp43HT+mO9opPmkNNuP3awmq2tG2L2R9gKhwhfuT9nR8+lb6QN+DwsOfiV?= =?us-ascii?Q?UjuZ8y8M2A=3D=3D?= X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 141e2d47-ef31-4a60-a746-08de4ecf989f X-MS-Exchange-CrossTenant-AuthSource: DU2PR04MB8951.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Jan 2026 16:04:26.1718 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: VHS7+Umktx+RAqaBEaHHnFTMaHJpzScOCo9qK3g2qij7YWlT+iMesyG8zMl7PJ2quHbSGtq//ZbmwYG4d5W+vg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DU4PR04MB11361 On Thu, Jan 08, 2026 at 03:43:03PM +0800, Xu Yang wrote: > 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 > Signed-off-by: Xu Yang > --- > drivers/usb/gadget/function/uvc.h | 2 +- > drivers/usb/gadget/function/uvc_video.c | 7 +++++-- > 2 files changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h > index b3f88670bff801a43d084646974602e5995bb192..676419a049762f9eb59e1ac68b19fa34f153b793 100644 > --- a/drivers/usb/gadget/function/uvc.h > +++ b/drivers/usb/gadget/function/uvc.h > @@ -107,7 +107,7 @@ struct uvc_video { > unsigned int width; > unsigned int height; > unsigned int imagesize; > - unsigned int interval; > + unsigned int interval; /* in 100ns units */ > struct mutex mutex; /* protects frame parameters */ > > unsigned int uvc_num_requests; > diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c > index 1c0672f707e4e5f29c937a1868f0400aad62e5cb..b1c5c1d3e9390c82cc84e736a7f288626ee69d51 100644 > --- a/drivers/usb/gadget/function/uvc_video.c > +++ b/drivers/usb/gadget/function/uvc_video.c > @@ -499,7 +499,7 @@ uvc_video_prep_requests(struct uvc_video *video) > { > struct uvc_device *uvc = container_of(video, struct uvc_device, video); > struct usb_composite_dev *cdev = uvc->func.config->cdev; > - unsigned int interval_duration = video->ep->desc->bInterval * 1250; > + unsigned int interval_duration; > unsigned int max_req_size, req_size, header_size; > unsigned int nreq; > > @@ -513,8 +513,11 @@ uvc_video_prep_requests(struct uvc_video *video) > return; > } > > + interval_duration = int_pow(2, video->ep->desc->bInterval - 1); 2 << (video->ep->desc->bInterval - 1) or BIT(video->ep->desc->bInterval - 1); int_pow() use while loop. slice better. Reviewed-by: Frank Li Frank > if (cdev->gadget->speed < USB_SPEED_HIGH) > - interval_duration = video->ep->desc->bInterval * 10000; > + interval_duration *= 10000; > + else > + interval_duration *= 1250; > > nreq = DIV_ROUND_UP(video->interval, interval_duration); > > > -- > 2.34.1 >