At Thu, 13 May 2010 10:21:26 +0800,
Wu Fengguang wrote:
>
> On Wed, May 12, 2010 at 06:55:09PM +0800, Takashi Iwai wrote:
> > At Wed, 12 May 2010 12:20:33 +0200,
> > Clemens Ladisch wrote:
> > >
> > > Takashi Iwai wrote:
> > > > Wu Fengguang wrote:
> > > > > > Jaroslav Kysela wrote:
> > > > > > > I don't agree to have only 4 slots for soundcards in the static minor
> > > > > > > numbering. Maybe the driver should be converted to use subdevices or we
> > > > > > > might drop the static minor number allocation at all (it might have only
> > > > > > > impact for old distros).
> > > > >
> > > > > Jaroslav, will there be so many sound cards in one system?
> > > >
> > > > In the old time, yes. Now we have less and less PCI slots.
> > > > In theory, we may have lots of USB audio devices, though :)
> > >
> > > I implemented CONFIG_SND_DYNAMIC_MINORS because people had been asking
> > > for more than eight cards. (And by now I have lots of cards too,
> > > although my computer probably isn't very typical.)
> > >
> > > Anyway, static numbering is needed only for systems without udev/devfs,
> > > and there we shouldn't change it for backwards compatibility. The HDA
> > > driver already requires kernels >= 2.6, so I don't see a problem with
> > > requiring CONFIG_SND_DYNAMIC_MINORS to get all HDMI outputs.
> >
> > Right. We can make it dependent.
> >
>
> Like this?
>
> config SND_HDA_CODEC_INTELHDMI
> bool "Build INTEL HDMI HD-audio codec support"
> + select SND_DYNAMIC_MINORS
> default y
>
> That will effectively turn on CONFIG_SND_DYNAMIC_MINORS by default
> (distribution kernels will have to enable it).
It's always a question whether we use "depends on" or "select".
The former is safer while the latter is more intuitive.
In this particular case, I think "select" would be OK.
If other guys have no objection, please repost the patch so that I can
pick it up later.
> Another backwards compatible solution is to fall back to the two
> reserved values. This makes me a bit more comfortable :)
As mentioned in another post, I don't see a big merit by it.
In short: don't touch a working code :) The non-dynamic minors are
only for old stuff, better to keep as is.
thanks,
Takashi
> --- drm-intel.orig/include/sound/minors.h 2010-05-13 10:06:52.000000000 +0800
> +++ drm-intel/include/sound/minors.h 2010-05-13 10:10:06.000000000 +0800
> @@ -35,7 +35,9 @@
> #define SNDRV_MINOR_TIMER (SNDRV_MINOR_GLOBAL + 1 * 32)
>
> #ifndef CONFIG_SND_DYNAMIC_MINORS
> - /* 2 - 3 (reserved) */
> +
> +#define SNDRV_MINOR_BACKUP1 2
> +#define SNDRV_MINOR_BACKUP2 3
> #define SNDRV_MINOR_HWDEP 4 /* 4 - 7 */
> #define SNDRV_MINOR_RAWMIDI 8 /* 8 - 15 */
> #define SNDRV_MINOR_PCM_PLAYBACK 16 /* 16 - 23 */
> --- drm-intel.orig/sound/core/sound.c 2010-05-13 10:06:04.000000000 +0800
> +++ drm-intel/sound/core/sound.c 2010-05-13 10:11:19.000000000 +0800
> @@ -269,8 +269,14 @@ int snd_register_device_for_dev(int type
> minor = snd_find_free_minor();
> #else
> minor = snd_kernel_minor(type, card, dev);
> - if (minor >= 0 && snd_minors[minor])
> - minor = -EBUSY;
> + if (minor >= 0) {
> + if (snd_minors[minor])
> + minor = SNDRV_MINOR_BACKUP1;
> + if (snd_minors[minor])
> + minor = SNDRV_MINOR_BACKUP2;
> + if (snd_minors[minor])
> + minor = -EBUSY;
> + }
> #endif
> if (minor < 0) {
> mutex_unlock(&sound_mutex);
>
> Thanks,
> Fengguang
>
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