Re: via82cxxx_audio locking problems

[David Chow <davidchow@rcn.com.hk>]

David Chow ¼g¹D¡G
> 
> Adrian Cox ¼g¹D¡G
> >
> > Jeff Garzik wrote:
> >
> > > On Thu, 20 Sep 2001, Thomas Sailer wrote:
> > >>   Dropping and reacquiring syscall_sem around interruptible_sleep_on
> > >>   in via_dsp_do_read, via_dsp_do_write and via_dsp_drain_playback
> > >>   should solve the problem. Does anyone see a problem with this?
> >
> > > Is there a possibility of do_read being re-entered during that window?
> > > I agree its a problem but the solution sounds racy?
> >
> > What's probably needed is one semaphore to lock read/write and ioctls
> > that look at the playback engine, and another semaphore to lock accesses
> > to the AC97 codec. That may be simpler to implement than dropping and
> > releasing the syscall_sem.
> >
> > --
> > Adrian Cox   http://www.humboldt.co.uk/
> >
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> 
> I receive the same problem when probing the via sound module. Since I am
> in a motherboard design project which I also uses the AC97 interface
> from VIA. The sample board from VIA didn't have any problem, but have 3
> motherboard from 3rd party, each of them uses the VIA694X + VIA686A,
> only one of them have no problem using the sound module, I think it is a
> hardware problem or the module itself didn't handle some cases. It seems
> it should be the same for hardware design, since different codec may
> have different effect on the module. All boards are tested with
> Windows98 and Linux and then all works fine runnign Windows. The sample
> board from VIA is a VIA694T + VIA686B which all of them are pin-2-pin
> compatible with the old 694X+686A. I am sure the problem is from the
> driver, but it is hardware dependent??? My board design just use exactly
> the same chips of the VIA sample board, then we will be save using the
> via_82cxxx module properly. I will try to find out which codec is the
> trouble boards using. The one I'm surely stable without locking is using
> the VIA codec VT1611A . Does you guys require more information about the
> codec specs? I can get them from VIA if you want. Thanks.
> 
> regards,
> 
> David
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Just find out the board that cause lock up both uses a Yamaha codec.