$SUBJ

$ git describe
v2.6.33-rc2

No matter if I actually play any sounds that process consumes 23-24% CPU
Don't know if it's related to above: even if there is no any sound activity
I can hear crackling in headphones.

$ lspci -vvv

00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 03)
        Subsystem: Hewlett-Packard Company Device 30c9
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 27
        Region 0: Memory at e0644000 (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-
        Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+
                Address: 00000000fee0300c  Data: 4191
        Capabilities: [70] Express (v1) Root Complex Integrated Endpoint, MSI 00
                DevCap: MaxPayload 128 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
                        ExtTag- RBE- FLReset-
                DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
                        RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+
                        MaxPayload 128 bytes, MaxReadReq 128 bytes
                DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr+ TransPend-
                LnkCap: Port #0, Speed unknown, Width x0, ASPM unknown, Latency L0 <64ns, L1 <1us
                        ClockPM- Surprise- LLActRep- BwNot-
                LnkCtl: ASPM Disabled; Disabled- Retrain- CommClk-
                        ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed unknown, Width x0, TrErr- Train- SlotClk- DLActive- BWMgmt- ABWMgmt-
        Capabilities: [100] Virtual Channel <?>
        Capabilities: [130] Root Complex Link <?>
        Kernel driver in use: HDA Intel
        Kernel modules: snd-hda-intel

$ powertop

Cn                Avg residency       P-states (frequencies)
C0 (cpu running)        (25.1%)         1200 Mhz     4.7%
C1                0.0ms ( 0.0%)         1067 Mhz     0.2%
C2                0.3ms (74.9%)          933 Mhz     0.2%
                                         800 Mhz    94.9%


Wakeups-from-idle per second : 2931.9   interval: 10.0s
no ACPI power usage estimate available

Top causes for wakeups:
  80.6% (6766.8)       <interrupt> : HDA Intel 
  10.5% (885.6)      <kernel IPI> : Rescheduling interrupts 
   6.4% (541.3)     <kernel core> : hrtimer_start_range_ns (tick_sched_timer) 
...

Thanks!

-- 

  Sergei