[alsa-devel] [bisected] lx6464es fails to open a second time
tiwai at suse.de
Tue Nov 22 11:26:46 CET 2011
At Tue, 22 Nov 2011 11:17:45 +0100,
Tim Blechmann wrote:
> > > today, i was able to bisect the issue and the first bad commit is:
> > >
> > > commit 6175ddf06b6172046a329e3abfd9c901a43efd2e
> > > Author: Brian Gerst <brgerst at gmail.com>
> > > Date: Fri Feb 5 09:37:07 2010 -0500
> > >
> > > x86: Clean up mem*io functions.
> > >
> > > the communication with the device is done by passing simple commands via
> > > memcpy_fromio and memcpy_toio (compare sound/pci/lx6464es/lx_core.c,
> > > lines 75 to 99). any idea, what is going wrong there?
> > The old and new implementations of memcpy_*io do not have any differences
> > in the documented API, but the new ones are much more optimized, so they
> > might not use 8- or 32-bit accesses or a different access pattern.
> > Does the card's mapped I/O region behave exactly like memory, or has it
> > any restrictions on how it can be used? In the latter case, you should
> > implement your readbuf/writebuf functions by hand to use plain 32-bit
> > accesses in order (or whatever is required).
> indeed, emulating memcpy_*io with ioread32/iowrite32 fixes the issue.
Good to hear. Could you submit a patch?
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