Subject: Re: mod to the ess driver?
To: Nathan J. Williams <nathanw@MIT.EDU>
From: Brett Lymn <>
List: current-users
Date: 09/18/2000 10:43:20
According to Nathan J. Williams:
>>         I have a Digital HiNote Ultra II laptop which has an ess sound
>> chip in it.  The ess driver probes it as a ess1788 chip but the probe
>> bombs out complaining it cannot set a bit in a register.  I tracked
>> this down in the driver and, just for kicks, made the error
>> non-fatal.  Doing this made the sound work, where the value of work is
>> "can play mp3's @ 44.1k in stereo".  
>Please test recording as well.

Recording appears to work fine too - managed to snarf a CD sample from
the mic input that sounded not too different when played back (sounded
good to me actually)

>I have the ESS-1788 manual; it's only avaliable in dead-tree form, and
>a little annoying to find the person who will send you a copy.

Hmmm ok, the passion wanes on getting one then.  Most unfortunate
given that a lot of chip manufacturers put that stuff on their web
sites as .pdf's these days which I think is far better all round (I am
crusty enough to remember the days before the internet really took off
when suppliers would give you dead-tree-form databooks years out of
date, getting up to date ones was near on impossible)

>But anyway, bit 2 of mixer register 0x64 is:
>"Bit 2: 1: Enable H/W volume interrupt request to use IRQE
> (potentially sharing with MPU-401)"
>It's not a crucial bit, certainly. We don't use the volume interrupt,
>and that toggling in ess_identify() doesn't seem like it really helps
>identifying an ESS chip (at that point we've already done a successful
>reset and read of the ID register).

OK - it sounds to me like either a) we lose the test altogether or b)
print a warning (hmmm maybe not by default) and go on with life.

> I do wonder why it doesn't work, though.

My experience with laptops is that they have the weirdest hardware
setups imaginable.  It is almost as if the manufacturers go out of
their way to make life difficult and don't think if you stick with the
same manufacturer you are ok, oh no, they change just about everything
between models.  It takes me days to get everything sorted when I
change laptops.

>If we can't figure out what that probe is good for, it should probably
>just be removed.

Sounds good to me.

Brett Lymn, Computer Systems Administrator, BAE SYSTEMS