Em Tue, 27 Mar 2018 17:45:57 +0100 Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx> escreveu: > 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 ) > > Tested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> > Tested-by: Philipp Zabel <philipp.zabel@xxxxxxxxx> > > 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 Kieran/Laurent, What's the status of this patchset? Regards, Mauro > > Kieran Bingham (6): > 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 > > drivers/media/usb/uvc/uvc_isight.c | 6 +- > drivers/media/usb/uvc/uvc_queue.c | 102 +++++++++++++---- > drivers/media/usb/uvc/uvc_video.c | 180 +++++++++++++++++++++--------- > drivers/media/usb/uvc/uvcvideo.h | 59 ++++++++-- > 4 files changed, 266 insertions(+), 81 deletions(-) > > base-commit: a77cfdf6bd06eef0dadea2b541a7c01502b1b4f6 Thanks, Mauro
