Re: Linux-2.4.20-pre4-ac1: i810_audio broken

Doug Ledford
2002-08-28T15:17:18Z

On Wed, Aug 28, 2002 at 04:22:30PM +0300, Andris Pavenis wrote:
> On Wednesday 28 August 2002 15:51, Juergen Sawinski wrote:
> > Can you drop in the old (working) source into the new tree and see if
> > that works? If that works I'll try making a step by step patch series,
> > to see what breaks it.
>
> Today's tests were done in that way (I only replaced i810_audio.c,
> removed i810_audio.o, run 'make modules' and 'make modules_install' and tested
> the results). As I wrote earlier it seems that Dough's patch (to
> 2.4.20-pre1-ac2) broke driver

(In an email Juergen sent to me privately he mentioned that on the ICH4
the CIV register is now read-only where as on previous ICH chips it was
read-write, which is something I missed as far as changes to the chip are
concerned)

Now, given the tidbit of information above, I would expect ICH4 chipsets
to break with the driver. We currently rely upon the ability to set the
CIV register to what we want in order to start the DMA where we want. If
that's now readonly, I'll have to rethink how I reset the DMA hardware and
how I will have to start recording the new DMA position instead of setting
the new DMA position. The one thing about this though, I would expect
this issue to cause previously non-working ICH4 chips to work poorly with
my patch instead of previously working ICH4 chips to now start working
poorly since my patch didn't change the (/me stops mid-sentence and
realizes that "yes, in fact there is a change in my patch to base DMA
operations that could cause this"). Hmmm...backup....try backing out my
changes to stop_dac and stop_adc (the part where I change how we do a DMA
engine reset every time we stop the dac and adc) and see if that solves
your problem. The changes to __stop_dac() and __stop_adc() are localized
actually and you should be able to safely leave all of those hunks out
without effecting the rest of the patch.

--
Doug Ledford <dledford@redhat.com> 919-754-3700 x44233
Red Hat, Inc.
1801 Varsity Dr.
Raleigh, NC 27606