Hi Kieran,
Thank you for the patches.
On Tuesday, 6 November 2018 23:27:11 EET Kieran Bingham wrote:
> From: Kieran Bingham <kieran.bing...@ideasonboard.com>
>
> The Linux UVC driver has long provided adequate performance capabilities for
> web-cams and low data rate video devices in Linux while resolutions were
> low.
>
> Modern USB cameras are now capable of high data rates thanks to USB3 with
> 1080p, and even 4k capture resolutions supported.
>
> Cameras such as the Stereolabs ZED (bulk transfers) or the Logitech BRIO
> (isochronous transfers) can generate more data than an embedded ARM core is
> able to process on a single core, resulting in frame loss.
>
> A large part of this performance impact is from the requirement to
> ‘memcpy’ frames out from URB packets to destination frames. This unfortunate
> requirement is due to the UVC protocol allowing a variable length header,
> and thus it is not possible to provide the target frame buffers directly.
>
> Extra throughput is possible by moving the actual memcpy actions to a work
> queue, and moving the memcpy out of interrupt context thus allowing work
> tasks to be scheduled across multiple cores.
>
> This series has been tested on both the ZED and BRIO cameras on arm64
> platforms, and with thanks to Randy Dunlap, a Dynex 1.3MP Webcam, a Sonix
> USB2 Camera, and a built in Toshiba Laptop camera, and with thanks to
> Philipp Zabel for testing on a Lite-On internal Laptop Webcam, Logitech
> C910 (USB2 isoc), Oculus Sensor (USB3 isoc), and Microsoft HoloLens Sensors
> (USB3 bulk).
>
> As far as I am aware iSight devices, and devices which use UVC to encode
> data (output device) have not yet been tested - but should find no ill
> effect (at least not until they are tested of course :D )
:-D
I'm not sure whether anyone is still using those devices with Linux. I
wouldn't be surprised if we realized down the road that they already don't
work.
> Tested-by: Randy Dunlap <rdun...@infradead.org>
> Tested-by: Philipp Zabel <philipp.za...@gmail.com>
>
> v2:
> - Fix race reported by Guennadi
>
> v3:
> - Fix similar race reported by Laurent
> - Only queue work if required (encode/isight do not queue work)
> - Refactor/Rename variables for clarity
>
> v4:
> - (Yet another) Rework of the uninitialise path.
> This time to hopefully clean up the shutdown races for good.
> use usb_poison_urb() to halt all URBs, then flush the work queue
> before freeing.
> - Rebase to latest linux-media/master
>
> v5:
> - Provide lockdep validation
> - rename uvc_queue_requeue -> uvc_queue_buffer_requeue()
> - Fix comments and periods throughout
> - Rebase to media/v4.20-2
> - Use GFP_KERNEL allocation in uvc_video_copy_data_work()
> - Fix function documentation for uvc_video_copy_data_work()
> - Add periods to the end of sentences
> - Rename 'decode' variable to 'op' in uvc_video_decode_data()
> - Move uvc_urb->async_operations initialisation to before use
> - Move async workqueue to match uvc_streaming lifetime instead of
> streamon/streamoff
> - bracket the for_each_uvc_urb() macro
>
> - New patches added to series:
> media: uvcvideo: Split uvc_video_enable into two
> media: uvcvideo: Rename uvc_{un,}init_video()
> media: uvcvideo: Utilise for_each_uvc_urb iterator
>
> Kieran Bingham (9):
> media: uvcvideo: Refactor URB descriptors
> media: uvcvideo: Convert decode functions to use new context structure
> media: uvcvideo: Protect queue internals with helper
> media: uvcvideo: queue: Simplify spin-lock usage
> media: uvcvideo: queue: Support asynchronous buffer handling
> media: uvcvideo: Move decode processing to process context
> media: uvcvideo: Split uvc_video_enable into two
I've taken the above patches in my tree.
> media: uvcvideo: Rename uvc_{un,}init_video()
> media: uvcvideo: Utilise for_each_uvc_urb iterator
And I've sent review comments for these two.
> drivers/media/usb/uvc/uvc_driver.c | 2 +-
> drivers/media/usb/uvc/uvc_isight.c | 6 +-
> drivers/media/usb/uvc/uvc_queue.c | 110 +++++++++---
> drivers/media/usb/uvc/uvc_video.c | 282 +++++++++++++++++++-----------
> drivers/media/usb/uvc/uvcvideo.h | 65 ++++++-
> 5 files changed, 331 insertions(+), 134 deletions(-)
>
> base-commit: dafb7f9aef2fd44991ff1691721ff765a23be27b
--
Regards,
Laurent Pinchart
