From efdc8a9585ce02e70e538e46f235aefd63a3f8da Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sun, 18 Jan 2009 17:46:30 -0300 Subject: [PATCH] V4L/DVB (10295): uvcvideo: Retry URB buffers allocation when the system is low on memory. URB buffers for video transfers are sized to UVC_MAX_PACKETS bulk/isochronous packets by default. If the system is too low on memory try successively smaller numbers of packets until allocation succeeds. Tested-by: Johannes Berg Signed-off-by: Laurent Pinchart Reviewed-by: Johannes Berg Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/uvc/uvc_video.c | 79 +++++++++++++++-------------- drivers/media/video/uvc/uvcvideo.h | 6 +-- 2 files changed, 44 insertions(+), 41 deletions(-) diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c index 9bc4705be78..7ebb89539c3 100644 --- a/drivers/media/video/uvc/uvc_video.c +++ b/drivers/media/video/uvc/uvc_video.c @@ -699,27 +699,47 @@ static void uvc_free_urb_buffers(struct uvc_video_device *video) * already allocated when resuming from suspend, in which case it will * return without touching the buffers. * - * Return 0 on success or -ENOMEM when out of memory. + * Limit the buffer size to UVC_MAX_PACKETS bulk/isochronous packets. If the + * system is too low on memory try successively smaller numbers of packets + * until allocation succeeds. + * + * Return the number of allocated packets on success or 0 when out of memory. */ static int uvc_alloc_urb_buffers(struct uvc_video_device *video, - unsigned int size) + unsigned int size, unsigned int psize, gfp_t gfp_flags) { + unsigned int npackets; unsigned int i; /* Buffers are already allocated, bail out. */ if (video->urb_size) return 0; - for (i = 0; i < UVC_URBS; ++i) { - video->urb_buffer[i] = usb_buffer_alloc(video->dev->udev, - size, GFP_KERNEL, &video->urb_dma[i]); - if (video->urb_buffer[i] == NULL) { - uvc_free_urb_buffers(video); - return -ENOMEM; + /* Compute the number of packets. Bulk endpoints might transfer UVC + * payloads accross multiple URBs. + */ + npackets = DIV_ROUND_UP(size, psize); + if (npackets > UVC_MAX_PACKETS) + npackets = UVC_MAX_PACKETS; + + /* Retry allocations until one succeed. */ + for (; npackets > 1; npackets /= 2) { + for (i = 0; i < UVC_URBS; ++i) { + video->urb_buffer[i] = usb_buffer_alloc( + video->dev->udev, psize * npackets, + gfp_flags | __GFP_NOWARN, &video->urb_dma[i]); + if (!video->urb_buffer[i]) { + uvc_free_urb_buffers(video); + break; + } + } + + if (i == UVC_URBS) { + video->urb_size = psize * npackets; + return npackets; } } - video->urb_size = size; return 0; } @@ -753,29 +773,19 @@ static int uvc_init_video_isoc(struct uvc_video_device *video, { struct urb *urb; unsigned int npackets, i, j; - __u16 psize; - __u32 size; + u16 psize; + u32 size; - /* Compute the number of isochronous packets to allocate by dividing - * the maximum video frame size by the packet size. Limit the result - * to UVC_MAX_ISO_PACKETS. - */ psize = le16_to_cpu(ep->desc.wMaxPacketSize); psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3)); - size = video->streaming->ctrl.dwMaxVideoFrameSize; - if (size > UVC_MAX_FRAME_SIZE) - return -EINVAL; - npackets = DIV_ROUND_UP(size, psize); - if (npackets > UVC_MAX_ISO_PACKETS) - npackets = UVC_MAX_ISO_PACKETS; + npackets = uvc_alloc_urb_buffers(video, size, psize, gfp_flags); + if (npackets == 0) + return -ENOMEM; size = npackets * psize; - if (uvc_alloc_urb_buffers(video, size) < 0) - return -ENOMEM; - for (i = 0; i < UVC_URBS; ++i) { urb = usb_alloc_urb(npackets, gfp_flags); if (urb == NULL) { @@ -814,25 +824,20 @@ static int uvc_init_video_bulk(struct uvc_video_device *video, struct usb_host_endpoint *ep, gfp_t gfp_flags) { struct urb *urb; - unsigned int pipe, i; - __u16 psize; - __u32 size; - - /* Compute the bulk URB size. Some devices set the maximum payload - * size to a value too high for memory-constrained devices. We must - * then transfer the payload accross multiple URBs. To be consistant - * with isochronous mode, allocate maximum UVC_MAX_ISO_PACKETS per bulk - * URB. - */ + unsigned int npackets, pipe, i; + u16 psize; + u32 size; + psize = le16_to_cpu(ep->desc.wMaxPacketSize) & 0x07ff; size = video->streaming->ctrl.dwMaxPayloadTransferSize; video->bulk.max_payload_size = size; - if (size > psize * UVC_MAX_ISO_PACKETS) - size = psize * UVC_MAX_ISO_PACKETS; - if (uvc_alloc_urb_buffers(video, size) < 0) + npackets = uvc_alloc_urb_buffers(video, size, psize, gfp_flags); + if (npackets == 0) return -ENOMEM; + size = npackets * psize; + if (usb_endpoint_dir_in(&ep->desc)) pipe = usb_rcvbulkpipe(video->dev->udev, ep->desc.bEndpointAddress); diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h index 027947ea9b6..b2639878f9b 100644 --- a/drivers/media/video/uvc/uvcvideo.h +++ b/drivers/media/video/uvc/uvcvideo.h @@ -296,10 +296,8 @@ struct uvc_xu_control { /* Number of isochronous URBs. */ #define UVC_URBS 5 -/* Maximum number of packets per isochronous URB. */ -#define UVC_MAX_ISO_PACKETS 40 -/* Maximum frame size in bytes, for sanity checking. */ -#define UVC_MAX_FRAME_SIZE (16*1024*1024) +/* Maximum number of packets per URB. */ +#define UVC_MAX_PACKETS 32 /* Maximum number of video buffers. */ #define UVC_MAX_VIDEO_BUFFERS 32 /* Maximum status buffer size in bytes of interrupt URB. */ -- 2.41.0