2010/10/19 Greg KH <greg@xxxxxxxxx>:
> On Sun, Oct 17, 2010 at 06:43:10AM +1100, Andrew Worsley wrote:
>> I am writing a USB driver modeled on the drivers/usb/usb-skeleton.c
>> version 2.6.30 but it gets the following warning.
>> I wonder if it is a generic issue, perhaps the skeleton is not
>> maintained any more? Alternatively perhaps I haven't implemented
>> things properly.
>
> Probably because no one tests the driver.
>
> Can you verify that the latest version (2.6.36, which is 2 years newer
> than the version you are using) still has this problem? If so, care to
> post your driver code you are using so we can see what the issue is?
Yes, the problem does exists in the latest kernel.
Also the warning will always be triggered in the HCD with
HCD_LOCAL_MEM flag set for any data transfer.
We have discussed the question before in the link below:
http://marc.info/?t=128469670800002&r=1&w=2
but seems no one knows why dma_free_coherent can't be used
with irq disabled.
IMO, we should make clear the reason above, then decide what to fix.
--
Lei Ming
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