diff options
| author |   Thomas Petazzoni <thomas.petazzoni@free-electrons.com> | 2012-01-07 09:52:37 -0300 |
|---|---|---|
| committer |   Mauro Carvalho Chehab <mchehab@redhat.com> | 2012-01-10 22:38:59 -0200 |
| commit | 7a6f6c29d264cdd2fe0eb3d923217eed5f0ad134 (patch) | |
| tree | fc2044a0b5f6300cafbae08285c84e8f9bc55fee /drivers/media/video/cx231xx/cx231xx-audio.c | |
| parent | [media] cx231xx: simplify argument passing to cx231xx_init_dev() (diff) | |
| download | linux-dev-7a6f6c29d264cdd2fe0eb3d923217eed5f0ad134.tar.xz linux-dev-7a6f6c29d264cdd2fe0eb3d923217eed5f0ad134.zip | |
[media] cx231xx: use URB_NO_TRANSFER_DMA_MAP on URBs allocated with usb_alloc_urb()
URBs allocated with usb_alloc_urb() are allocated from DMA-coherent
areas, and therefore it is not necessary to call dma_map_single() on
such buffers. Worst, on ARM, calling dma_map_single() on a
DMA-coherent buffer will trigger a BUG_ON() in
arch/arm/mm/dma-mapping.c.
Therefore, we mark all URBs allocated with usb_alloc_urb() with the
URB_NO_TRANSFER_DMA_MAP transfer_flags, so that the USB core does not
do dma_map_single()/dma_unmap_single() on those buffers.
This is similar to 882787ff8fdeb0be790547ee9b22b281095e95da for the
gspca driver, and has already been discussed on the linux-media list
in the past:
http://www.mail-archive.com/linux-media@vger.kernel.org/msg37086.html.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/cx231xx/cx231xx-audio.c')
| -rw-r--r-- | drivers/media/video/cx231xx/cx231xx-audio.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/media/video/cx231xx/cx231xx-audio.c b/drivers/media/video/cx231xx/cx231xx-audio.c index e5742a0e19a0..a2c2b7d343ec 100644 --- a/drivers/media/video/cx231xx/cx231xx-audio.c +++ b/drivers/media/video/cx231xx/cx231xx-audio.c @@ -307,7 +307,7 @@ static int cx231xx_init_audio_isoc(struct cx231xx *dev) urb->context = dev; urb->pipe = usb_rcvisocpipe(dev->udev, dev->adev.end_point_addr); - urb->transfer_flags = URB_ISO_ASAP; + urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP; urb->transfer_buffer = dev->adev.transfer_buffer[i]; urb->interval = 1; urb->complete = cx231xx_audio_isocirq; @@ -368,7 +368,7 @@ static int cx231xx_init_audio_bulk(struct cx231xx *dev) urb->context = dev; urb->pipe = usb_rcvbulkpipe(dev->udev, dev->adev.end_point_addr); - urb->transfer_flags = 0; + urb->transfer_flags = URB_NO_TRANSFER_DMA_MAP; urb->transfer_buffer = dev->adev.transfer_buffer[i]; urb->complete = cx231xx_audio_bulkirq; urb->transfer_buffer_length = sb_size; |