[alsa-devel] Backported sbxfi driver (UNTESTED!)

[Takashi Iwai]

At Fri, 17 Oct 2008 13:58:20 +0400,
The Source wrote:
> 
> Takashi Iwai пишет:
> > At Fri, 17 Oct 2008 11:57:08 +0400,
> > The Source wrote:
> >   
> >> Takashi Iwai пишет:
> >>     
> >>> At Thu, 16 Oct 2008 22:18:07 +0400,
> >>> The Source wrote:
> >>>   
> >>>       
> >>>>>> Ok. OpenAL with alsa also seem to cause problems.
> >>>>>>     
> >>>>>>         
> >>>>>>             
> >>>>> In both cases, check the period_size and buffer_size values (shown in
> >>>>> the kernel message, or /proc/asound/card0/pcm0p/sub0/hw_params).
> >>>>> And, try to aplay with these parameters, whether you get the similar
> >>>>> problem.
> >>>>>
> >>>>> 	% aplay -v --period-size=xxx --buffer-size=yyy foo.wav
> >>>>>
> >>>>>
> >>>>> Takashi
> >>>>>
> >>>>>   
> >>>>>       
> >>>>>           
> >>>> I'm sorry, but any attemp to play file with ossplay results in complete 
> >>>> system hang with error:
> >>>> unable to handle NULL ponter dereference at address 
> >>>> 0000000000000008.....(hang, no more output).
> >>>> I tried many wav formats. So I can't get error log or period and buffer 
> >>>> sizes, sorry.
> >>>>     
> >>>>         
> >>> Can anyone confirm to reproduce Oops with OSS apps (ossplay)?
> >>>
> >>> I'm wondering whether this has anything to do with the capture.
> >>> Can you record the sound, and change the capture mixer element properly?
> >>>
> >>>
> >>> thanks,
> >>>
> >>> Takashi
> >>>
> >>>   
> >>>       
> >> I checked mplayer. It uses period size 1024 instead of 4096 and 16384 
> >> buffer size (default). Sound is choppy (sound pauses is more frequent 
> >> when rate is lower).
> >> However an attempt to play the same file with the same period and buffer 
> >> sizes with aplay results in complete system hang.
> >>     
> >
> > OK, that looks like a problem.  Looks like the timer resolution can be
> > short like that, or something racy in the timer handling.
> >
> > Can you check whether this happens with XXX_SYSTEM_TIMER, too?
> >
> > Or, does the patch below avoid the problem, at least?
> >
> >
> > thanks,
> >
> > Takashi
> >
> > diff --git a/sound/pci/sbxfi/sbxfi.c b/sound/pci/sbxfi/sbxfi.c
> > index 26a6cd3..5ceb228 100644
> > --- a/sound/pci/sbxfi/sbxfi.c
> > +++ b/sound/pci/sbxfi/sbxfi.c
> > @@ -277,6 +277,7 @@ static void sbxfi_rearm_timer(struct sbxfi *chip, int ticks)
> >  #else
> >  
> >  #define MAX_TICKS	((1 << 13) - 1)
> > +#define MIN_TICKS	1000		/* FIXME: really so? */
> >  
> >  static void sbxfi_init_timer(struct sbxfi *chip)
> >  {
> > @@ -287,6 +288,8 @@ static void sbxfi_set_timer(struct sbxfi *chip, int ticks)
> >  	LOG(2, "SET TIMER TICKS = %d\n", ticks);
> >  	if (ticks > MAX_TICKS)
> >  		ticks = MAX_TICKS;
> > +	else if (ticks < MIN_TICKS)
> > +		ticks = MIN_TICKS;
> >  	sbxfi_write(chip, TIMR, ticks | TIMR_IE | TIMR_IP);
> >  }
> >  static void sbxfi_stop_timer(struct sbxfi *chip)
> >
> >   
> After patch:
> 
> Without system timer:
> 
> aplay --period-size=1024 96000_16_Stereo.wav
> Plays fine
> 
> aplay --period-size=1024 22050_16_Mono.wav
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
> Hang
> 
> With system timer:
> 
> aplay --period-size=1024 96000_16_Stereo.wav
> Superglitch. Each sample is played many times before advancing to next one.
> 
> aplay --period-size=1024 22050_16_Mono.wav
> Instant reboot.

Just to be sure: you don't enable XXX_CONT_RATE, right?
It's known to be buggy, so disabled as default now.


Takashi