From: Michael Grzeschik m.grzeschik@pengutronix.de
commit 19905240aef0181d1e6944070eb85fce75f75bcd upstream.
The overhead of preparing sg data is high for transfers with limited payload. When transferring isoc over high-speed usb the maximum payload is rather small which is a good argument no to use sg. This patch is changing the uvc_video_encode_isoc_sg encode function only to be used for super speed gadgets.
Signed-off-by: Michael Grzeschik m.grzeschik@pengutronix.de Cc: stable stable@kernel.org Link: https://lore.kernel.org/r/20221017221141.3134818-1-m.grzeschik@pengutronix.d... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/gadget/function/uvc_queue.c | 9 +++------ drivers/usb/gadget/function/uvc_video.c | 9 +++++++-- 2 files changed, 10 insertions(+), 8 deletions(-)
--- a/drivers/usb/gadget/function/uvc_queue.c +++ b/drivers/usb/gadget/function/uvc_queue.c @@ -84,12 +84,9 @@ static int uvc_buffer_prepare(struct vb2 return -ENODEV;
buf->state = UVC_BUF_STATE_QUEUED; - if (queue->use_sg) { - buf->sgt = vb2_dma_sg_plane_desc(vb, 0); - buf->sg = buf->sgt->sgl; - } else { - buf->mem = vb2_plane_vaddr(vb, 0); - } + buf->sgt = vb2_dma_sg_plane_desc(vb, 0); + buf->sg = buf->sgt->sgl; + buf->mem = vb2_plane_vaddr(vb, 0); buf->length = vb2_plane_size(vb, 0); if (vb->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) buf->bytesused = 0; --- a/drivers/usb/gadget/function/uvc_video.c +++ b/drivers/usb/gadget/function/uvc_video.c @@ -448,6 +448,9 @@ static void uvcg_video_pump(struct work_ */ int uvcg_video_enable(struct uvc_video *video, int enable) { + struct uvc_device *uvc = video->uvc; + struct usb_composite_dev *cdev = uvc->func.config->cdev; + struct usb_gadget *gadget = cdev->gadget; unsigned int i; int ret;
@@ -479,9 +482,11 @@ int uvcg_video_enable(struct uvc_video * if (video->max_payload_size) { video->encode = uvc_video_encode_bulk; video->payload_size = 0; - } else - video->encode = video->queue.use_sg ? + } else { + video->encode = (video->queue.use_sg && + !(gadget->speed <= USB_SPEED_HIGH)) ? uvc_video_encode_isoc_sg : uvc_video_encode_isoc; + }
video->req_int_count = 0;