linux/drivers/usb/gadget
Avichal Rakesh 28d900836d usb: gadget: uvc: queue empty isoc requests if no video buffer is available
[ Upstream commit c3ff12a92b ]

ISOC transfers expect a certain cadence of requests being queued. Not
keeping up with the expected rate of requests results in missed ISOC
transfers (EXDEV). The application layer may or may not produce video
frames to match this expectation, so uvc gadget driver must handle cases
where the application is not queuing up buffers fast enough to fulfill
ISOC requirements.

Currently, uvc gadget driver waits for new video buffer to become available
before queuing up usb requests. With this patch the gadget driver queues up
0 length usb requests whenever there are no video buffers available. The
USB controller's complete callback is used as the limiter for how quickly
the 0 length packets will be queued. Video buffers are still queued as
soon as they become available.

Link: https://lore.kernel.org/CAMHf4WKbi6KBPQztj9FA4kPvESc1fVKrC8G73-cs6tTeQby9=w@mail.gmail.com/
Signed-off-by: Avichal Rakesh <arakesh@google.com>
Link: https://lore.kernel.org/r/20230508231103.1621375-1-arakesh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-08-23 17:52:23 +02:00
..
function usb: gadget: uvc: queue empty isoc requests if no video buffer is available 2023-08-23 17:52:23 +02:00
legacy USB: gadget: Fix the memory leak in raw_gadget driver 2023-08-03 10:24:07 +02:00
udc USB: Gadget: core: Help prevent panic during UVC unconfigure 2023-08-16 18:27:24 +02:00
composite.c usb: gadget: call usb_gadget_check_config() to verify UDC capability 2023-08-03 10:24:07 +02:00
config.c usb: fix various gadget panics on 10gbps cabling 2021-06-09 10:40:08 +02:00
configfs.c usb: gadget: configfs: Restrict symlink creation is UDC already binded 2023-03-10 09:33:35 +01:00
configfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
epautoconf.c usb: gadget: fix for a typo that conveys logically-inverted information. 2021-09-14 10:27:54 +02:00
functions.c USB: add SPDX identifiers to all remaining files in drivers/usb/ 2017-11-04 11:48:02 +01:00
Kconfig media: Kconfig: cleanup VIDEO_DEV dependencies 2022-03-18 05:58:35 +01:00
Makefile usb: gadget: Makefile: remove ccflags-y 2022-03-18 12:56:08 +01:00
u_f.c usb: gadget: Change Andrzej Pietrasiewicz's e-mail address 2019-02-11 11:12:29 +02:00
u_f.h USB: gadget: u_f: Unbreak offset calculation in VLAs 2020-08-27 09:25:06 +02:00
u_os_desc.h usb: gadget: Change Andrzej Pietrasiewicz's e-mail address 2019-02-11 11:12:29 +02:00
usbstring.c usb: gadget: fix langid kernel-doc warning in usbstring.c 2020-07-09 10:13:07 +03:00