[alsa-devel] HDA - AD1986a issues.

Tobin Davis tdavis at dsl-only.net
Mon Feb 4 17:38:10 CET 2008

On Mon, 2008-02-04 at 16:19 +0100, Takashi Iwai wrote:

> At Fri, 01 Feb 2008 14:57:35 -0800,
> Tobin Davis wrote:
> > 
> > On Fri, 2008-02-01 at 16:13 +0100, Takashi Iwai wrote:
> > 
> >     > Also, I had some very strange audio garbage with the tip on an HD Audio
> >     platform
> >     > that normally works ok.  I'm going to be tracking it down this morning,
> >     once I
> >     > get to work (1 hour).  I'm not sure if it is related to the AD1986a or the
> >     SCH
> >     > (gcap patch).
> >    
> >     AD1986A has a known problem when you assign the single stream to
> >     multiple DACs.  But, we should have fixed this already in 1.0.16rc2.
> > 
> > Ok, I can confirm on my test system that the HDA-GCAP and HDA-SCH patches are
> > ok.  I tested them on 1.0.15 with an AD1986a and they work fine.  Same system
> > with HG20080130 is aweful.  I'm trying to revert the patch_analog patches one at
> > a time to see which one is the problem.
> Did you find out the problem?  I vaguely remember that EAPD may play a
> bad role for headphones.  This should be disabled except for the
> speaker output.

The problem I noticed only occurred on my SCH based system.  It was
solved with the snoop bit check/set.  I'll double check to see if I have
any issues on my laptop (Asus Z62F w/ ad1986a - model=laptop-eapd).

Oddly enough, the system worked fine with 1.0.15 and the two earlier
patches (GCAP and SCH PCI IDS).  Not sure what to make of that.  I'll do
more testing today.

> >     >  I do know that GCAP returns 2200 on this system, whereas a normal
> >     > ICH returns 4401.  The last bit may be significant (64bit vs 32bit
> >     stream).  I
> >     > need to reverify the SCH value, but this may be causing the issue.  This
> >     is
> >     > critical for a launch coming up.
> >    
> >     Hm, this bit hasn't been tested.  OK, we need a fix for that.
> > 
> > No need to worry about this bit I guess.  It may only be relevant on a system
> > that runs 64bit OSes, and I'd assume that bit doesn't exist for systems that
> > can't.
> The fix itself would be pretty easy.  Check this bit and reset the dma
> consistent mask to 32bit if it's 32bit only.
> Hm, this reminds me that we should call set_mask with 64bit as
> default.  Needs more investigation...

Is this dependent on system/OS?  My thought was it was for supporting
x86-64 architecture.  That being the case, it should be added to the
TODO list, but not critical for 1.0.16 release.  

Actually, there are other potential issues that I noticed with regards
to GCAP and our current usage.  For example, bi-directional stream
support and number of serial data out signals.  Both are hardwired in
the ICH family of chipsets, but for how long?

Tobin Davis 

Better dead than mellow.

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