Messages in this thread Patch in this message | | | Date | Mon, 23 Jan 2012 15:41:07 -0800 | From | Greg KH <> | Subject | [21/27] USB: Fix bad dma problem on WDM device disconnect |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
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From: Robert Lukassen <Robert.Lukassen@tomtom.com>
commit 878b753e32ca765cd346a5d3038d630178ec78ff upstream. [ changed s/usb_free_coherent/usb_buffer_free/ for 2.6.32.x]
In the WDM class driver a disconnect event leads to calls to usb_free_coherent to put back two USB DMA buffers allocated earlier. The call to usb_free_coherent uses a different size parameter (desc->wMaxCommand) than the corresponding call to usb_alloc_coherent (desc->bMaxPacketSize0).
When a disconnect event occurs, this leads to 'bad dma' complaints from usb core because the USB DMA buffer is being pushed back to the 'buffer-2048' pool from which it has not been allocated.
This patch against the most recent linux-2.6 kernel ensures that the parameters used by usb_alloc_coherent & usb_free_coherent calls in cdc-wdm.c match.
Signed-off-by: Robert Lukassen <robert.lukassen@tomtom.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Bjørn Mork <bjorn@mork.no>
--- drivers/usb/class/cdc-wdm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -277,7 +277,7 @@ static void cleanup(struct wdm_device *d desc->sbuf, desc->validity->transfer_dma); usb_buffer_free(interface_to_usbdev(desc->intf), - desc->wMaxCommand, + desc->bMaxPacketSize0, desc->inbuf, desc->response->transfer_dma); kfree(desc->orq);
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