This fixes a WARN_ON_ONCE(!dev->dma_mask) in dma_map_page_attrs(). The PWC driver does not perform DMA operations itself. The USB bus controller does. Hence the mapping should be performed for that device. The bus controller has the DMA mask set, since it actually interacts with the hardware, where as the PWC driver does not.
Cc: stable@vger.kernel.org # 5.10 Signed-off-by: Andrew Lunn andrew@lunn.ch ---
I don't hang out in the media subsystem mailing list, being a network hacker. So i don't know the local customs here.
This patch is based on git://linuxtv.org/media_tree.git branch fixes. Please let me know if it needs rebasing to somewhere else.
I did not do a git bisect. I do know v5.9 works, v5.10 regressed. I cannot give an exact Fixes: tag as a result. It would be nice to get it into stable for 5.10, but it does not need to go any further back.
drivers/media/usb/pwc/pwc-if.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/media/usb/pwc/pwc-if.c b/drivers/media/usb/pwc/pwc-if.c index 61869636ec61..406cc0268c7b 100644 --- a/drivers/media/usb/pwc/pwc-if.c +++ b/drivers/media/usb/pwc/pwc-if.c @@ -461,7 +461,7 @@ static int pwc_isoc_init(struct pwc_device *pdev) urb->pipe = usb_rcvisocpipe(udev, pdev->vendpoint); urb->transfer_flags = URB_ISO_ASAP | URB_NO_TRANSFER_DMA_MAP; urb->transfer_buffer_length = ISO_BUFFER_SIZE; - urb->transfer_buffer = pwc_alloc_urb_buffer(&udev->dev, + urb->transfer_buffer = pwc_alloc_urb_buffer(udev->bus->controller, urb->transfer_buffer_length, &urb->transfer_dma); if (urb->transfer_buffer == NULL) { @@ -515,6 +515,7 @@ static void pwc_iso_stop(struct pwc_device *pdev)
static void pwc_iso_free(struct pwc_device *pdev) { + struct usb_device *udev = pdev->udev; int i;
/* Freeing ISOC buffers one by one */ @@ -524,7 +525,7 @@ static void pwc_iso_free(struct pwc_device *pdev) if (urb) { PWC_DEBUG_MEMORY("Freeing URB\n"); if (urb->transfer_buffer) - pwc_free_urb_buffer(&urb->dev->dev, + pwc_free_urb_buffer(udev->bus->controller, urb->transfer_buffer_length, urb->transfer_buffer, urb->transfer_dma);