When i plug a ZC3xx usb webcam to the host port of fsl_imx51pdk(arm),
the system crashes like this:
usb 1-1: new full speed USB device using fsl-ehci and address 2
gspca: probing 0ac8:301b
zc3xx: probe sensor -> 000a
zc3xx: Find Sensor PB0330. Chip revision 0
input: zc3xx as /devices/platform/fsl-ehci.0/usb1/1-1/input/input0
gspca: video1 created
gspca: found int in endpoint: 0x82, buffer_len=8, interval=10
kernel BUG at /home/hwang4/work/build/51/build/linux/arch/arm/mm/\
dma-mapping.c:411!
Unable to handle kernel NULL pointer dereference at virtual address \
00000000
pgd = c0004000
[00000000] *pgd=00000000
Internal error: Oops: 817 [#1] PREEMPT
This is because we alloc buffer for an urb through usb_buffer_alloc,
the alloced buffer is already in DMA coherent region, so we should
set the flag of this urb to URB_NO_TRANSFER_DMA_MAP, otherwise when
we submit this urb, the hcd core will handle this address as an
non-DMA address and call dma_map_single/sg to map it. On arm
architecture, dma_map_single a DMA coherent address will be catched
by a BUG_ON().
Signed-off-by: Jason Wang <jason77.wang@xxxxxxxxx>
---
drivers/media/video/gspca/gspca.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/drivers/media/video/gspca/gspca.c b/drivers/media/video/gspca/gspca.c
index b984610..78abc1c 100644
--- a/drivers/media/video/gspca/gspca.c
+++ b/drivers/media/video/gspca/gspca.c
@@ -223,6 +223,7 @@ static int alloc_and_submit_int_urb(struct gspca_dev *gspca_dev,
usb_rcvintpipe(dev, ep->bEndpointAddress),
buffer, buffer_len,
int_irq, (void *)gspca_dev, interval);
+ urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
gspca_dev->int_urb = urb;
ret = usb_submit_urb(urb, GFP_KERNEL);
if (ret < 0) {
--
1.5.6.5
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