[Cbe-oss-dev] PCM device not found

[Masakazu Mokuno]

Hi Michael,

On Mon, 26 May 2008 13:14:38 +0200
<Michael.Schoeller at inhouse.wko.at> wrote:

> The kernel build with the config generated with make ps3_defconfig has ps3 sound support enabled. However after booting with that kernel the PCM device is not found and no sound is playing.
> I already tried activating all options found in the kernel config submenu "Device Drivers>Sound" and it's submenus but that did not solve the problem.
> I came to the conclusion that there must be an other option in the kernelconfig that has to be activated or there is a bug in the current kernel sources.
> However that's far beyond my knowledge so maybe you can help me again.

With ps3_defconfig, the PS3 sound driver will be compiled as a module,
snd_ps3.ko. So snd_ps3.ko (and dependent alsa modules) should be loaded
before using the sound device.
If your system loads the modules and the PS3 sound driver starts
successfully, the driver shows a message in dmesg and lsmod shows snd_ps3
as a loaded module.

	# dmesg | grep sound
	PS3 sound started. start_delay=2000ms
	# lsmod
	Module                  Size  Used by
	hci_usb                21644  0 
	bluetooth              87900  1 hci_usb
	usb_storage            58160  0 
	snd_ps3                18312  0 
	snd_pcm               116840  1 snd_ps3
	snd_page_alloc         11768  1 snd_pcm
	snd_timer              33952  1 snd_pcm
	ehci_hcd               47076  0 
	snd                    76112  3 snd_ps3,snd_pcm,snd_timer
	ohci_hcd               31292  0 
	soundcore              11120  1 snd
	ps3_lpm                19128  0 
	sg                     47616  0 
	usbcore               186636  5 hci_usb,usb_storage,ehci_hcd,ohci_hcd


If there isn't, there's something wrong in handling module loading. 
Does your /lib/modules/`uname -r` have the proper modules?

	# ls -R /lib/modules/`uname -r`/kernel/sound
	/lib/modules/2.6.26-rc4-00508-ge490517-dirty/kernel/sound:
	core  ppc  soundcore.ko

	/lib/modules/2.6.26-rc4-00508-ge490517-dirty/kernel/sound/core:
	snd.ko  snd-page-alloc.ko  snd-pcm.ko  snd-timer.ko

	/lib/modules/2.6.26-rc4-00508-ge490517-dirty/kernel/sound/ppc:
	snd_ps3.ko

If the problem is module loading, the easy fix is to let the driver be
linked into the kernel.

diff -u .config.old .config
--- .config.old	2008-05-27 18:02:18.000000000 +0900
+++ .config	2008-05-27 18:05:31.000000000 +0900
@@ -1,7 +1,7 @@
 #
 # Automatically generated make config: don't edit
 # Linux kernel version: 2.6.26-rc4
-# Tue May 27 18:02:18 2008
+# Tue May 27 18:05:31 2008
 #
 CONFIG_PPC64=y
 
@@ -833,14 +833,14 @@
 #
 # Sound
 #
-CONFIG_SOUND=m
+CONFIG_SOUND=y
 
 #
 # Advanced Linux Sound Architecture
 #
-CONFIG_SND=m
-CONFIG_SND_TIMER=m
-CONFIG_SND_PCM=m
+CONFIG_SND=y
+CONFIG_SND_TIMER=y
+CONFIG_SND_PCM=y
 # CONFIG_SND_SEQUENCER is not set
 # CONFIG_SND_MIXER_OSS is not set
 # CONFIG_SND_PCM_OSS is not set
@@ -869,7 +869,7 @@
 #
 # ALSA PowerPC devices
 #
-CONFIG_SND_PS3=m
+CONFIG_SND_PS3=y
 CONFIG_SND_PS3_DEFAULT_START_DELAY=2000
 

Regards

-- 
Masakazu Mokuno