This is an automatic generated email to let you know that the following patch were queued at the http://git.linuxtv.org/media_tree.git tree:
Subject: [media] media: Fix a UVC performance problem on systems with non-coherent DMA Author: Al Cooper <[email protected]> Date: Thu Aug 18 10:28:29 2011 -0300 The UVC driver uses usb_alloc_coherent() to allocate DMA data buffers. On systems without coherent DMA this ends up allocating buffers in uncached memory. The subsequent memcpy's done to coalesce the DMA chunks into contiguous buffers then run VERY slowly. On a MIPS test system the memcpy is about 200 times slower. This issue prevents the system from keeping up with 720p YUYV data at 10fps. The following patch uses kmalloc to alloc the DMA buffers instead of usb_alloc_coherent on systems without coherent DMA. With this patch the system was easily able to keep up with 720p at 10fps. Signed-off-by: Al Cooper <[email protected]> Acked-by: Laurent Pinchart <[email protected]> Signed-off-by: Mauro Carvalho Chehab <[email protected]> drivers/media/video/uvc/uvc_video.c | 17 ++++++++++++++++- 1 files changed, 16 insertions(+), 1 deletions(-) --- http://git.linuxtv.org/media_tree.git?a=commitdiff;h=3e0ac6717b0a2593243ef3850025a42cb199880f diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c index ffd1158..b015e8e 100644 --- a/drivers/media/video/uvc/uvc_video.c +++ b/drivers/media/video/uvc/uvc_video.c @@ -790,8 +790,12 @@ static void uvc_free_urb_buffers(struct uvc_streaming *stream) for (i = 0; i < UVC_URBS; ++i) { if (stream->urb_buffer[i]) { +#ifndef CONFIG_DMA_NONCOHERENT usb_free_coherent(stream->dev->udev, stream->urb_size, stream->urb_buffer[i], stream->urb_dma[i]); +#else + kfree(stream->urb_buffer[i]); +#endif stream->urb_buffer[i] = NULL; } } @@ -831,9 +835,14 @@ static int uvc_alloc_urb_buffers(struct uvc_streaming *stream, for (; npackets > 1; npackets /= 2) { for (i = 0; i < UVC_URBS; ++i) { stream->urb_size = psize * npackets; +#ifndef CONFIG_DMA_NONCOHERENT stream->urb_buffer[i] = usb_alloc_coherent( stream->dev->udev, stream->urb_size, gfp_flags | __GFP_NOWARN, &stream->urb_dma[i]); +#else + stream->urb_buffer[i] = + kmalloc(stream->urb_size, gfp_flags | __GFP_NOWARN); +#endif if (!stream->urb_buffer[i]) { uvc_free_urb_buffers(stream); break; @@ -908,10 +917,14 @@ static int uvc_init_video_isoc(struct uvc_streaming *stream, urb->context = stream; urb->pipe = usb_rcvisocpipe(stream->dev->udev, ep->desc.bEndpointAddress); +#ifndef CONFIG_DMA_NONCOHERENT urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP; + urb->transfer_dma = stream->urb_dma[i]; +#else + urb->transfer_flags = URB_ISO_ASAP; +#endif urb->interval = ep->desc.bInterval; urb->transfer_buffer = stream->urb_buffer[i]; - urb->transfer_dma = stream->urb_dma[i]; urb->complete = uvc_video_complete; urb->number_of_packets = npackets; urb->transfer_buffer_length = size; @@ -969,8 +982,10 @@ static int uvc_init_video_bulk(struct uvc_streaming *stream, usb_fill_bulk_urb(urb, stream->dev->udev, pipe, stream->urb_buffer[i], size, uvc_video_complete, stream); +#ifndef CONFIG_DMA_NONCOHERENT urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; urb->transfer_dma = stream->urb_dma[i]; +#endif stream->urb[i] = urb; } _______________________________________________ linuxtv-commits mailing list [email protected] http://www.linuxtv.org/cgi-bin/mailman/listinfo/linuxtv-commits
