From: Kay Sievers <kay.sievers@vrfy.org>
To: Greg KH <greg@kroah.com>
Cc: Jaroslav Kysela <perex@suse.cz>,
LKML <linux-kernel@vger.kernel.org>, Takashi Iwai <tiwai@suse.de>
Subject: Re: sysfs & ALSA card
Date: Sat, 07 Oct 2006 14:55:30 +0200 [thread overview]
Message-ID: <1160225730.19302.1.camel@localhost> (raw)
In-Reply-To: <20061007074440.GA9304@kroah.com>
On Sat, 2006-10-07 at 00:44 -0700, Greg KH wrote:
> > On Fri, Oct 06, 2006 at 04:00:27PM +0200, Jaroslav Kysela wrote:
> > > I would like to discuss where is the right root for soundcards in
> > > the sysfs tree. I would like to put card specific variables like id there
> > > (see /proc/asound/card0/id).
> > > Also, I plan to create link from
> > > /sys/class/sound tree to the appropriate card to show relationship.
> > > Something like:
> > >
> > > /sys/<somewhere>/soundcard/0
> > >
> > > /sys/class/sound/controlC0/soundcard -> ../../../<somewhere>/soundcard/0
> > >
> > > Any comments and suggestions?
No, please no links if you have stuff that can be expressed in a tree,
which you perfectly can in this case. Just create a parent "card-device"
to hold the generic card attributes, and put the stuff like pcmC0* below
that device. Userspace is fine with that and will not break,
cause /sys/class/sound/* is still just a flat directory with all devices
in one directory, only the link targets will point to a hierarchy (note
that the link target of "pcmC1D0c" includes" Audigy2". )
> Here's what /sys/class/sound now looks like for me:
> $ tree /sys/class/sound/
> /sys/class/sound/
> |-- Audigy2 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2
> |-- admmidi1 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/admmidi1
> |-- amidi1 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/amidi1
> |-- controlC1 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/controlC1
> |-- dmmidi1 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/dmmidi1
> |-- hwC1D0 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/hwC1D0
> |-- midi1 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/midi1
> |-- midiC1D0 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/midiC1D0
> |-- midiC1D1 -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/midiC1D1
> |-- pcmC1D0c -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/pcmC1D0c
> |-- pcmC1D0p -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/pcmC1D0p
> |-- pcmC1D1c -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/pcmC1D1c
> |-- pcmC1D2c -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/pcmC1D2c
> |-- pcmC1D2p -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/pcmC1D2p
> |-- pcmC1D3p -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/pcmC1D3p
> |-- pcmC1D4c -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/pcmC1D4c
> |-- pcmC1D4p -> ../../devices/pci0000:00/0000:00:1e.0/0000:06:0d.0/Audigy2/pcmC1D4p
> `-- timer -> ../../devices/virtual/sound/timer
>
>
> Yeah, I picked the wrong name for the card, it should be "card1" instead
> of "Audigy2" here, but you get the idea.
That looks nice. Yeah, it should something that matches to the C1 in the
other names.
> Please also note that you will need the latest versions of udev to get
> this to work properly for your sysfs nodes.
This should be fine for all recent releases including SLE.
Thanks,
Kay
next prev parent reply other threads:[~2006-10-07 12:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-06 14:00 sysfs & ALSA card Jaroslav Kysela
2006-10-07 6:24 ` Greg KH
2006-10-07 7:44 ` Greg KH
2006-10-07 12:55 ` Kay Sievers [this message]
2006-10-07 19:12 ` Kay Sievers
2006-10-07 20:08 ` Greg KH
2006-10-09 6:24 ` Jaroslav Kysela
2006-10-11 22:52 ` Greg KH
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