Re: [RFC PATCH] ES938 support for ES18xx driver

[Ondrej Zary <linux@rainbow-software.org>]

On Sunday 15 September 2013 22:35:20 Andreas Mohr wrote:
> Hi,
>
> On Sun, Sep 15, 2013 at 10:25:45PM +0200, Ondrej Zary wrote:
> > On Sunday 15 September 2013 20:49:02 Andreas Mohr wrote:
> > BTW. I've got an AZT3328 card and it works fine with your driver. Thanks
> > for it.
>
> What!?!? I didn't quite expect any kernel dev to have that one, too ;)

Don't remember where I got it from but it looked nice so I bought it :)

> (got several commits sitting here and waiting for submission though)
>
> > I'm thinking about doing some reverse-engineering of thunderbird-based
> > sound cards (VLSI Thunderbird - Aztech PCI 368-DSP, Thunderbird Avenger -
> > Philips Acoustic/Seismic/Rhythmic Edge).
>
> Oh, nice. I've got the Aztech PCI 368-DSP, too (that was somewhat
> obligatory due to having written another Aztech card driver...).
>
> And yeah, the PCI 368 (etc.) series does seem to be some rather heavy
> support hole indeed, IIRC (especially as it's more modern PCI-based and not
> ISA).

Got it on eBay but the Philips Edge cards are not that uncommon - they were 
sold here (in Slovakia) too, IIRC. I have Seismic Edge PSC705 (but bought it 
used).

> > > So perhaps ES938 has (perhaps since it might more or less conform to
> > > certain standards specs?) another control for PCM output switch as well
> > > which would need implementing or simply isn't set properly?
> > > (to clarify, we're talking about a switch which would cause output
> > > signal to be grabbed pre or post the 3D manipulation block)
> >
> > The good thing is that there's a datasheet available for ES938 - e.g. at
> > http://www.datasheetarchive.com/ES938-datasheet.html
> >
> > The 3D switch works but the level doesn't. Maybe I should use only the 3
> > specific level values from the datasheet and not a variable scale. Or
> > just remove the level control completely as Windows driver does (there's
> > only a 3D switch).
>
> Hmm. Perhaps they removed it "Since It Does Not Work"? ;-P

Maybe. The value is configured in the INF file and never changed.

> Thanks for hinting at the TLV control dB values thingy! Didn't know that
> such thing existed, thus azt3328 does not have it (yet?).

It's a nice thing, especially for cards that can go above 0 dB. You then know 
that the sound can be distorted when you set e.g. PCM volume too high.

> > > Perhaps we could have a more verbose message here?
> > > That ES938 surely must have some human-readable characteristics...
> > > (hmm, what about "ES938 3D audio effects processor found!"?)
> > > ((or "Detected ..."))
> >
> > Yes, that's wrong - it's only for testing purposes. There should probably
> > be no message at all as the es18xx driver itself does not display
> > anything if everything is OK.
>
> ...or that, yeah.
>
> > > Perhaps that check is not specific enough, i.e. it might be useful
> > > to figure out a more precise check?
> >
> > snd_es938_read_reg() checks that the returned data match the format used
> > by ES938. Maybe we can reread all the register values back after writing
> > to be sure.
>
> Is there any chip ID/version register to be identified?

No, there are only 8 registers, all(? - haven't tested) R/W.

-- 
Ondrej Zary