Hi List,

This is just an updated repost of my request from a month ago. So far I have not achieved to solve the problem myselves, therefore I would very much appreciate ANY hint as to what (and even more important: where) to look for.

Here is a summary of my problem and some related info:

I am experiencing severely scratching and stuttering sound on my nVidia MCP78S (GeForce 8200) based Asus M3N78-EMH HDMI mainboard, which has an ALC883 on board, running with an Athlon X2 4850e dual-core CPU. It sounds, as if the sound buffers are not filled in time and are therefore repeated many times (2 to 4 times) per second. The problem seems to be kernel / alsa-driver related, because I experience the problem also when running runlevel 1 with only a minimum of active processes (e.g. without graphics).

Strange enough, the sound is OK when I do a larger compilation in parallel (kernel make with make -j 2), but the sound is not OK when I run burnK7 (two instances to sufficiently load both CPU cores) => What is different in CPU loading or scheduling between these two load cases? Also, the sound is OK when I copy large files in parallel.

Could it be related, that lspci gives me for all devices a latency of 0, even though the kernel message tell me that it was set to 64? I cannot change the PCI latency to another value via setpci.

I am using Message Signal Interrupts for HD Audio, although switching it off also makes no audible difference. My Interrupt distribution is: CPU0 CPU1 0: 39 1 IO-APIC-edge timer 1: 61 27962 IO-APIC-edge i8042 6: 0 5 IO-APIC-edge floppy 7: 1 0 IO-APIC-edge 8: 0 1 IO-APIC-edge rtc0 9: 0 0 IO-APIC-fasteoi acpi 20: 826 748020 IO-APIC-fasteoi nvidia 22: 0 3 IO-APIC-fasteoi ehci_hcd:usb2, ehci_hcd:usb4 23: 437 175388 IO-APIC-fasteoi ohci_hcd:usb1, ohci_hcd:usb3 314: 2891 1330645 PCI-MSI-edge eth1 315: 0 0 PCI-MSI-edge cx23885[0] 316: 258 115865 PCI-MSI-edge HDA Intel 317: 286 118802 PCI-MSI-edge ahci NMI: 0 0 Non-maskable interrupts LOC: 977113 1020994 Local timer interrupts RES: 327021 99771 Rescheduling interrupts CAL: 1408 972 function call interrupts TLB: 11275 4795 TLB shootdowns TRM: 0 0 Thermal event interrupts THR: 0 0 Threshold APIC interrupts SPU: 0 0 Spurious interrupts ERR: 1

I tried several things so far: Debian kernel image 2.6.25-2-amd64 (2.6.25-5 and 2.6.25-7) Ubuntu 8.04 with kernel 2.6.24-16 self-compiled 2.6.25.x (with x in nothing to 5), with and without -rt patches self-compiled 2.6.26-rc5 to 2.6.26 final latest alsa-driver 1.0.17rc2, 1.0.17-rc3 and 1.0.17 alsa-library versions 1.0.16 and 1.0.17

all these versions give the similar distorted output.

please find the alsa-info output here: http://pastebin.ca/1077615 (previously posted info: http://pastebin.ca/1052359 )

attached is my latest kernel setup (2.6.26, alsa driver modules now replaced by version 1.0.17).

Please tell me your suggestions what the problem may be or how I could debug the problem. Thanks very much.