On my laptop, the sound card auto mutes some seconds after i enable it.
And play a audio file can't make sound. This is not a powersave feature,
because i haven't enable it. I guess it's a driver problem. It occurs
since 2.6.36.X. Please help.

Card: Audio device: ATI Technologies Inc SBx00 Azalia (Intel HDA)
Module: snd_hda_codec_analog, snd_hda_intel

The possible useful information are followed.
--------------------
[~]$ sh repository/kernel/scripts/ver_linux 
If some fields are empty or look unusual you may have an old version.
Compare to the current minimal requirements in Documentation/Changes.
 
Linux localhost 2.6.38-rc4 #2 SMP Tue Feb 8 19:46:16 CST 2011 x86_64 GNU/Linux
 
Gnu C                  4.4.5
Gnu make               3.81
binutils               2.20.1
util-linux             repository/kernel/scripts/ver_linux: 23: fdformat: not found
mount                  support
module-init-tools      found
Linux C Library        2.11.2
Dynamic linker (ldd)   2.11.2
Procps                 3.2.8
Console-tools          0.2.3
Sh-utils               8.5
Modules Loaded         snd_hda_codec_analog snd_hda_intel snd_hda_codec snd_pcm snd_seq snd_timer snd_seq_device snd usbhid hid soundcore psmouse snd_page_alloc evdev
[~]$ 

--------------------
root:~# lspci -vvv -s 00:14.02
00:14.2 Audio device: ATI Technologies Inc SBx00 Azalia (Intel HDA)
	Subsystem: Hewlett-Packard Company Device 30c2
	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=slow >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 64, Cache Line Size: 64 bytes
	Interrupt: pin ? routed to IRQ 16
	Region 0: Memory at a4000000 (64-bit, non-prefetchable) [size=16K]
	Capabilities: [50] Power Management version 2
		Flags: PMEClk- DSI- D1- D2- AuxCurrent=55mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
		Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
	Kernel driver in use: HDA Intel

root:~#

--------------------
root:~# cat /proc/version 
Linux version 2.6.38-rc4 (root@localhost) (gcc version 4.4.5 (Debian 4.4.5-10) ) #2 SMP Tue Feb 8 19:46:16 CST 2011
root:~# 

--------------------
root:~# dmesg |grep -i 14.2
pci 0000:00:14.2: [1002:4383] type 0 class 0x000403
pci 0000:00:14.2: reg 10: [mem 0xcc308000-0xcc30bfff 64bit]
pci 0000:00:14.2: PME# supported from D0 D3hot D3cold
pci 0000:00:14.2: PME# disabled
pci 0000:00:14.2: address space collision: [mem 0xcc308000-0xcc30bfff 64bit] conflicts with 0000:00:12.0 [mem 0xcc309000-0xcc3093ff]
pci 0000:00:14.2: BAR 0: assigned [mem 0xa4000000-0xa4003fff 64bit]
pci 0000:00:14.2: BAR 0: set to [mem 0xa4000000-0xa4003fff 64bit] (PCI address [0xa4000000-0xa4003fff])
rtc_cmos 00:05: setting system clock to 2011-02-09 13:14:28 UTC (1297257268)
HDA Intel 0000:00:14.2: power state changed by ACPI to D0
HDA Intel 0000:00:14.2: power state changed by ACPI to D0
HDA Intel 0000:00:14.2: PCI INT A -> GSI 16 (level, low) -> IRQ 16
root:~# 

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