usb_control_msg initiates (and waits for completion of) a dma transfer using
the supplied buffer. That buffer thus has to be seperately allocated on
the heap.
In lib/dma_debug.c the function check_for_stack even warns about it:
WARNING: at lib/dma-debug.c:866 check_for_stack
Note: This change is tested to compile only, as I don't have the hardware.
Signed-off-by: Florian Mickler <flor...@mickler.org>
---
drivers/media/dvb/dvb-usb/dw2102.c | 10 ++++++++--
1 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/media/dvb/dvb-usb/dw2102.c
b/drivers/media/dvb/dvb-usb/dw2102.c
index 2c307ba..4c8ff39 100644
--- a/drivers/media/dvb/dvb-usb/dw2102.c
+++ b/drivers/media/dvb/dvb-usb/dw2102.c
@@ -101,12 +101,16 @@ static int dw210x_op_rw(struct usb_device *dev, u8
request, u16 value,
u16 index, u8 * data, u16 len, int flags)
{
int ret;
- u8 u8buf[len];
-
+ u8 *u8buf;
unsigned int pipe = (flags == DW210X_READ_MSG) ?
usb_rcvctrlpipe(dev, 0) : usb_sndctrlpipe(dev,
0);
u8 request_type = (flags == DW210X_READ_MSG) ? USB_DIR_IN : USB_DIR_OUT;
+ u8buf = kmalloc(len, GFP_KERNEL);
+ if (!u8buf)
+ return -ENOMEM;
+
+
if (flags == DW210X_WRITE_MSG)
memcpy(u8buf, data, len);
ret = usb_control_msg(dev, pipe, request, request_type |
USB_TYPE_VENDOR,
@@ -114,6 +118,8 @@ static int dw210x_op_rw(struct usb_device *dev, u8 request,
u16 value,
if (flags == DW210X_READ_MSG)
memcpy(data, u8buf, len);
+
+ kfree(u8buf);
return ret;
}
--
1.7.4.1
--
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