Hi Mauro, On 15/05/18 20:22, Mauro Carvalho Chehab wrote: > 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? I believe v4 was my final version (until someone tells me otherwise), and fixed all known races. Unless there has been bitrot since I posted (was last rebased at v4.16-rc4 ?) ... It would be good to at least get it in -next for a while if not mainline... Laurent ? The latest version is available in a branch at : git://git.kernel.org/pub/scm/linux/kernel/git/kbingham/rcar.git uvc/async/v4 Let me know if I need to post a rebased version. -- Kieran > > 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 >
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