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| author | Michael Grzeschik <m.grzeschik@pengutronix.de> | 2021-06-28 17:53:10 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-07-27 15:59:19 +0200 |
| commit | e81e7f9a0eb9536d5976acf5d95290338032a198 (patch) | |
| tree | b6b77525a913fa96cc5271252257439647637bda /drivers/usb/gadget/function/uvc.h | |
| parent | b9b82d3d0dbc45ee6b4817c7a7275a65152301f5 (diff) | |
| download | lwn-e81e7f9a0eb9536d5976acf5d95290338032a198.tar.gz lwn-e81e7f9a0eb9536d5976acf5d95290338032a198.zip | |
usb: gadget: uvc: add scatter gather support
This patch adds support for scatter gather transfers. If the underlying
gadgets sg_supported == true, then the videeobuf2-dma-sg is used and the
encode routine maps all scatter entries to separate scatterlists for the
usb gadget.
When streaming 1080p with request size of 1024 times 3 bytes top shows a
difference of about 6.4% CPU load applying this patch:
PID USER PR NI VIRT RES %CPU %MEM TIME+ S COMMAND
64 root 0 -20 0.0m 0.0m 7.7 0.0 0:01.25 I [kworker/u5:0-uvcvideo]
83 root 0 -20 0.0m 0.0m 4.5 0.0 0:03.71 I [kworker/u5:3-uvcvideo]
307 root -51 0 0.0m 0.0m 3.8 0.0 0:01.05 S [irq/51-dwc3]
vs.
64 root 0 -20 0.0m 0.0m 5.8 0.0 0:01.79 I [kworker/u5:0-uvcvideo]
306 root -51 0 0.0m 0.0m 3.2 0.0 0:01.97 S [irq/51-dwc3]
82 root 0 -20 0.0m 0.0m 0.6 0.0 0:01.86 I [kworker/u5:1-uvcvideo]
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20210628155311.16762-5-m.grzeschik@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/gadget/function/uvc.h')
| -rw-r--r-- | drivers/usb/gadget/function/uvc.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index 52f894183ecf..36b78f8b3cd4 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -75,6 +75,8 @@ struct uvc_request { struct usb_request *req; u8 *req_buffer; struct uvc_video *video; + struct sg_table sgt; + u8 header[2]; }; struct uvc_video { |