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Date: Tue, 22 Nov 2011 11:26:46 +0100
Message-ID: <s5hobw4ihax.wl%tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Tim Blechmann <tim@klingt.org>
Cc: Clemens Ladisch <clemens@ladisch.de>, LKML <linux-kernel@vger.kernel.org>,
        alsa-devel@alsa-project.org, Brian Gerst <brgerst@gmail.com>
Subject: Re: [alsa-devel] [bisected] lx6464es fails to open a second time
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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@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?


thanks,

Takashi