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V4L/DVB (10295): uvcvideo: Retry URB buffers allocation when the system is low on memory.

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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 <johannes@sipsolutions.net>
Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Laurent Pinchart 2009-01-18 17:46:30 -03:00 committed by Mauro Carvalho Chehab
parent f61d1d8a56
commit efdc8a9585
2 changed files with 43 additions and 40 deletions
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77
drivers/media/video/uvc/uvc_video.c
View File

@ -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;
unsigned int npackets, 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.
*/
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);

6
drivers/media/video/uvc/uvcvideo.h
View File

@ -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. */