Re: OSS audio compatibility layer regression - Linux-3.x - unableto register OSS PCM device 0:0

[Wallak]

Takashi Iwai wrote:
> At Sat, 10 Dec 2011 20:32:54 +0100,
> wallak@xxxxxxx wrote:
> > I've an issue, when I use the SND_OSSEMUL compatibility layer with the
> > snd_intel8x0 module. The devices can't be registered. Indeed, theses devices are
> > registered at the oss_init() stage, and are not available later. A patch to fix
> > this issue is available below. The patch uses the previous linux behavior.
> I guess you set CONFIG_SOUND_OSS=y?  This conflicts with the OSS
> emulation.  It looked as if both can co-exist in the former kernels,
> but it's just because we didn't check it strictly.  Both try to
> register the very same devices -- especially OSS does this at init
> even before needed.
> As a workaround, just disable CONFIG_SOUND_OSS unless you really need
> it.  Or, if this isn't the case, give your .config file.
>
> If this is the case, we can add a Kconfig rule to exclude the
> conflict in future...
>
>
> thanks,
>
> Takashi

Thanks; I will update the .config file.

Best Regards,
Wallak.

> > Best Regards,
> > Wallak.
> >
> >
> > #log output
> > snd_intel8x0 0000:00:1f.5: PCI INT B ->  Link[LNKB] ->  GSI 10 (level, low) ->  IRQ
> > 10
> > intel8x0_measure_ac97_clock: measured 54899 usecs (2645 samples)
> > intel8x0: clocking to 48000
> > unable to register OSS PCM device 0:0
> > Bridge firewalling registered
> >
> > #patch fixing this issue: (commit 848669da3a92fa6ab815e0517af3294afb3ea928 adds
> > this issue)
> > --- linux-3.1.5-mdf/sound/oss/soundcard.c.orig    2011-12-09 17:57:05.000000000
> > +0100
> > +++ linux-3.1.5-mdf/sound/oss/soundcard.c    2011-12-10 15:18:02.000000000 +0100
> > @@ -526,21 +526,31 @@
> >   }
> >
> >
> > +/* These device names follow the official Linux device list,
> > + * Documentation/devices.txt.  Let us know if there are other
> > + * common names we should support for compatibility.
> > + * Only those devices not created by the generic code in sound_core.c are
> > + * registered here.
> > + */
> > +static const struct {
> > +    unsigned short minor;
> > +    char *name;
> > +    umode_t mode;
> > +    int *num;
> > +} dev_list[] = { /* list of minor devices */
> > +/* seems to be some confusion here -- this device is not in the device list */
> > +    {SND_DEV_DSP16,     "dspW",     S_IWUGO | S_IRUSR | S_IRGRP,
> > +&num_audiodevs},
> > +    {SND_DEV_AUDIO,     "audio",     S_IWUGO | S_IRUSR | S_IRGRP,
> > +&num_audiodevs},
> > +};
> > +
> >   static int dmabuf;
> >   static int dmabug;
> >
> >   module_param(dmabuf, int, 0444);
> >   module_param(dmabug, int, 0444);
> >
> > -/* additional minors for compatibility */
> > -struct oss_minor_dev {
> > -    unsigned short minor;
> > -    unsigned int enabled;
> > -} dev_list[] = {
> > -    { SND_DEV_DSP16 },
> > -    { SND_DEV_AUDIO },
> > -};
> > -
> >   static int __init oss_init(void)
> >   {
> >       int             err;
> > @@ -561,12 +571,18 @@
> >       sound_dmap_flag = (dmabuf>  0 ? 1 : 0);
> >
> >       for (i = 0; i<  ARRAY_SIZE(dev_list); i++) {
> > -        j = 0;
> > -        do {
> > -            unsigned short minor = dev_list[i].minor + j * 0x10;
> > -            if (!register_sound_special(&oss_sound_fops, minor))
> > -                dev_list[i].enabled = (1<<  j);
> > -        } while (++j<  num_audiodevs);
> > +        device_create(sound_class, NULL,
> > +                  MKDEV(SOUND_MAJOR, dev_list[i].minor), NULL,
> > +                  "%s", dev_list[i].name);
> > +
> > +        if (!dev_list[i].num)
> > +            continue;
> > +
> > +        for (j = 1; j<  *dev_list[i].num; j++)
> > +            device_create(sound_class, NULL,
> > +                      MKDEV(SOUND_MAJOR,
> > +                        dev_list[i].minor + (j*0x10)),
> > +                      NULL, "%s%d", dev_list[i].name, j);
> >       }
> >
> >       if (sound_nblocks>= MAX_MEM_BLOCKS - 1)
> > @@ -580,11 +596,11 @@
> >       int i, j;
> >
> >       for (i = 0; i<  ARRAY_SIZE(dev_list); i++) {
> > -        j = 0;
> > -        do {
> > -            if (dev_list[i].enabled&  (1<<  j))
> > -                unregister_sound_special(dev_list[i].minor);
> > -        } while (++j<  num_audiodevs);
> > +        device_destroy(sound_class, MKDEV(SOUND_MAJOR, dev_list[i].minor));
> > +        if (!dev_list[i].num)
> > +            continue;
> > +        for (j = 1; j<  *dev_list[i].num; j++)
> > +            device_destroy(sound_class, MKDEV(SOUND_MAJOR, dev_list[i].minor +
> > (j*0x10)));
> >       }
> >
> >       unregister_sound_special(1);

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