Re: USB transfer_buffer allocations on 64bit systems

[Daniel Mack]

On Wed, Apr 14, 2010 at 06:21:05PM +0100, Pedro Ribeiro wrote:
> On 14 April 2010 17:36, Daniel Mack <daniel@xxxxxxxx> wrote:
> > No worries - I agree. But unfortunately, I'm out of ideas now, and my
> > initial thoughts about what might cause the trouble were abviously not
> > able to explain the issue. Does anyone see further steps of tracking
> > this issue down?
> >
> > Thanks,
> > Daniel
> >
> 
> Well if this is a dirty / dangerous hack, what about your first patch?
> I've been testing it for days and has given me no problems.

[For those who haven't followed all the discussions - this patch used
 usb_buffer_alloc() instead of kmalloc() in the audio USB driver]

No, Alan is right. As long as we don't know what's going on, it
shouldn't be fixed that way.

There might be an update to all USB drivers to use a special allocation
function in order to avoid DMA bounce buffers for non-64-bit aware host
controllers, but that's certainly a second step. First, the bug that you
see needs attention, and the longer you can reproduce it, the better :)

Daniel
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/