[alsa-devel] [RFC][PATCH] fall back to reserved minor numbers

Wu Fengguang fengguang.wu at intel.com
Fri May 14 10:55:26 CEST 2010


On Fri, May 14, 2010 at 04:17:27PM +0800, Takashi Iwai wrote:
> At Fri, 14 May 2010 11:28:28 +0800,
> Wu Fengguang wrote:
> > 
> > When the static minor numbers collide because of too many devices,
> > fall back to the reserved minor numbers 2 and 3.
> > 
> > This for example will allow Intel HDMI audio driver to create three PCM
> > devices (index 3, 7, 8; the minor number of the last index will
> > otherwise collide with the first record device).
> > 
> > The other option is to force enable CONFIG_SND_DYNAMIC_MINORS.
> > 
> > Signed-off-by: Wu Fengguang <fengguang.wu at intel.com>
> 
> Well, frankly, I don't see a big merit of doing this.
> 
> Most (all?) 2.6-based distros are using udev, thus
> CONFIG_SND_DYNAMIC_MINORS should be used there.  The rest is for old
> distros or for some limited systems like embedded devices, and they
> won't need so much PCM devices.
> 
> Even if we do this, it doesn't make sense unless the user-space side
> creates the corresponding device node.

I was afraid of this case: an embedded system with G45 HDMI codec.
This codec only has 1 PCM playback device, however the driver still
requires enabling CONFIG_SND_DYNAMIC_MINORS in order to support more
capable HDMI codecs.

Thanks,
Fengguang


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