3e0ac6717b
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 <alcooperx@gmail.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| uvc_ctrl.c | ||
| uvc_driver.c | ||
| uvc_entity.c | ||
| uvc_isight.c | ||
| uvc_queue.c | ||
| uvc_status.c | ||
| uvc_v4l2.c | ||
| uvc_video.c | ||
| uvcvideo.h | ||