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V4L/DVB:usbvideo:don't use part of buffer for USB transfer #4 

The status[] is part of  uvc_device structure. We can't make sure
the address of status is at a cache-line boundary in all archs,so
status[] might share a cache-line with some fields in uvc_structure.
This can lead to some cache coherence issues(http://lwn.net/Articles/2265/).
Use dynamically allocated buffer instead.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Ming Lei 2008-09-16 03:32:20 -03:00 committed by Mauro Carvalho Chehab
parent d63beb9ef0
commit a31a405547
2 changed files with 13 additions and 4 deletions
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13
drivers/media/video/uvc/uvc_status.c
View File

@ -177,10 +177,16 @@ int uvc_status_init(struct uvc_device *dev)
uvc_input_init(dev);
dev->int_urb = usb_alloc_urb(0, GFP_KERNEL);
if (dev->int_urb == NULL)
dev->status = kzalloc(UVC_MAX_STATUS_SIZE, GFP_KERNEL);
if (dev->status == NULL)
return -ENOMEM;
dev->int_urb = usb_alloc_urb(0, GFP_KERNEL);
if (dev->int_urb == NULL) {
kfree(dev->status);
return -ENOMEM;
}
pipe = usb_rcvintpipe(dev->udev, ep->desc.bEndpointAddress);
/* For high-speed interrupt endpoints, the bInterval value is used as
@ -192,7 +198,7 @@ int uvc_status_init(struct uvc_device *dev)
interval = fls(interval) - 1;
usb_fill_int_urb(dev->int_urb, dev->udev, pipe,
dev->status, sizeof dev->status, uvc_status_complete,
dev->status, UVC_MAX_STATUS_SIZE, uvc_status_complete,
dev, interval);
return usb_submit_urb(dev->int_urb, GFP_KERNEL);
@ -202,6 +208,7 @@ void uvc_status_cleanup(struct uvc_device *dev)
{
usb_kill_urb(dev->int_urb);
usb_free_urb(dev->int_urb);
kfree(dev->status);
uvc_input_cleanup(dev);
}

4
drivers/media/video/uvc/uvcvideo.h
View File

@ -303,6 +303,8 @@ struct uvc_xu_control {
#define UVC_MAX_FRAME_SIZE (16*1024*1024)
/* Maximum number of video buffers. */
#define UVC_MAX_VIDEO_BUFFERS 32
/* Maximum status buffer size in bytes of interrupt URB. */
#define UVC_MAX_STATUS_SIZE 16
#define UVC_CTRL_CONTROL_TIMEOUT 300
#define UVC_CTRL_STREAMING_TIMEOUT 1000
@ -634,7 +636,7 @@ struct uvc_device {
/* Status Interrupt Endpoint */
struct usb_host_endpoint *int_ep;
struct urb *int_urb;
__u8 status[16];
__u8 *status;
struct input_dev *input;
/* Video Streaming interfaces */