Re: USB transfer_buffer allocations on 64bit systems

[Alan Stern]

On Wed, 14 Apr 2010, Pedro Ribeiro wrote:

> On 14 April 2010 22:01, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:
> > On Wed, Apr 14, 2010 at 04:29:22PM -0400, Alan Stern wrote:
> >> On Wed, 14 Apr 2010, Chris Wright wrote:
> >>
> >> > So dma_map_single is the case that's failing, but you think the mask is
> >> > correct?  What about the direction?
> >>
> >> The mask and direction are unquestionably correct.  The mask is set up
> >> by pci_setup_device() and not changed thereafter.  Furthermore, the
> >> audio works okay until another device (a DVB tuner) is plugged in.
> >
> > Could the driver for the DVB tuner change the PCI mask? That is, change
> > the pci mask way after it has been initialized (don't laugh, this did
> > happend - as I remember 4 months fix was posted on the DRM mailing list
> > for this).
> >
> 
> I can also trigger the bug on mount and unmount of a USB stick, albeit
> its not as intensive.

In addition, it's worth pointing out that the DVB tuner is another USB 
device, not a PCI device.  Hence it doesn't have a PCI driver, and it 
seems most unlikely that its driver would modify the DMA mask of a 
different device.

Alan Stern

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