At Tue, 8 Nov 2011 07:43:26 -0800, Linus Torvalds wrote:
Chris - you need to pick a better set of people to ask. A mailing list, right maintainer etc.
Takashi, any idea? Do we have some 8-sound-card limit somewhere?
I do see that we have that odd
if (card && card->number >= 8) return 0; /* ignore silently */in sound/core/sound_oss.c: snd_register_oss_device(), but it has no comments. The thing goes back to 2005 with the commit log entry of "[ALSA] dynamic minors (6/6): increase maximum number of sound cards", but the value '8'isn't explained.
ALSA itself can support 32 cards when CONFIG_SND_DYNAMIC_MINORS is set, which assumes the use of udev. Most of modern distros set this already. That's why Chris got already more than 8 devices seen in ALSA side.
The above code is, however, about OSS-emulation. And I guess it's just a left-over of the old static limitation. Actually OSS could support up to 16 cards (in theory).
Below is an untested fix patch. Does it work?
thanks,
Takashi
LinusOn Tue, Nov 8, 2011 at 12:30 AM, Chris Shen chris2shen@gmail.com wrote:
Hi,everyone! My version of kernel is linux-2.6.35 .And my board has 10 sounds cards.After system was up,I used the comand "aplay -l ".Then console would display this: **** List of PLAYBACK Hardware Devices **** card 0: imx3stack [imx-3stack], device 0: WM8731 WM8731-0 [] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: default [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 card 2: default_1 [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 card 3: default_2 [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 card 4: default_3 [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 card 5: default_4 [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 card 6: default_5 [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 card 7: default_6 [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 card 8: default_7 [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 card 9: default_8 [C-Media USB Headphone Set ], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 But,when I used the command "ls /dev/dsp*" ,the console display: /dev/dsp /dev/dsp2 /dev/dsp4 /dev/dsp6 /dev/dsp1 /dev/dsp3 /dev/dsp5 /dev/dsp7 when the board is up ,I found have this err "unable to register OSS mixer device 8:0" and "unable to register OSS mixer device 9:0" . I think the kernel's max sound cards is 8 .How can I modify it ? Thank you!
--- From: Takashi Iwai tiwai@suse.de Subject: [PATCH] ALSA: Fix the card number limit of OSS-emulation
There are left-over codes from the ancient days with the static device number limitation of 8. Actaully OSS can support up to 16 cards.
Signed-off-by: Takashi Iwai tiwai@suse.de --- sound/core/sound_oss.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/sound/core/sound_oss.c b/sound/core/sound_oss.c index c700920..075fc86 100644 --- a/sound/core/sound_oss.c +++ b/sound/core/sound_oss.c @@ -111,7 +111,7 @@ int snd_register_oss_device(int type, struct snd_card *card, int dev, int register1 = -1, register2 = -1; struct device *carddev = snd_card_get_device_link(card);
- if (card && card->number >= 8) + if (card && card->number >= SNDRV_MINOR_OSS_DEVICES) return 0; /* ignore silently */ if (minor < 0) return minor; @@ -170,7 +170,7 @@ int snd_unregister_oss_device(int type, struct snd_card *card, int dev) int track2 = -1; struct snd_minor *mptr;
- if (card && card->number >= 8) + if (card && card->number >= SNDRV_MINOR_OSS_DEVICES) return 0; if (minor < 0) return minor;