ALSA underruns occurr when using QEMU

I'm running QEMU 1.6.1 on a 64-bit Gentoo Linux system. The guest operating system is Windows 7 32-bit. I get multiple identical warning messages when using the ac97 or hda sound cards:

> ALSA lib /var/tmp/portage/media-libs/alsa-lib-1.0.27.2/work/alsa-lib-1.0.27.2/src/pcm/pcm.c:7843:(snd_pcm_recover) underrun occurred

The difference between ac97 and hda is that the former works well, while the latter causes the sound to be garbled.

/var/tmp/portage is the directory where Portage, the Gentoo package manager, builds programs. I don't know why it is mentioned in the error message.

I also don't know if this is an ALSA problem or a QEMU problem.

The command I use is:

> qemu-system-i386 -cpu host -m 1G -k it -drive file=~/QEMU/Windows_7_Privato.qcow2,media=disk,index=0 -vga std -net nic -net user -enable-kvm -display sdl -soundhw ac97 -device usb-ehci,id=ehci -usb -rtc base=localtime -usbdevice tablet

My real sound card is an Intel HD Audio:

> lspci | grep "Audio device"

> 00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 02)

Please tell me if you need other informations.

QEmu is more or less unusable here because of this:

ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
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ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred
ALSA lib pcm.c:7843:(snd_pcm_recover) underrun occurred


More info:

Host: Linux 4.3.3 vanilla/CentOS 6.7 i686
ALSA: alsa-lib-1.0.22-3.el6.i686

Qemu: 2.5

Triaging old bug tickets ... can you still reproduce this issue with the latest version of QEMU (currently v2.9)?

I'm still using Gentoo Linux on the same 64-bit system, and I can still reproduce this bug:

qemu-system-i386 -cpu host -m 1G -k it -drive file=~/qemu/windows-7-ultimate-x86.qcow2,media=disk,index=0 -vga std -net nic -net user -enable-kvm -display sdl -soundhw ac97 -device usb-ehci,id=ehci -usb -rtc base=localtime -usbdevice tablet
audio: Failed to create voice `ac97.pi'
audio: Failed to create voice `ac97.mc'
audio: Failed to create voice `ac97.pi'
audio: Failed to create voice `ac97.mc'
ALSA lib /var/tmp/portage/media-libs/alsa-lib-1.1.4/work/alsa-lib-1.1.4/src/pcm/pcm.c:8321:(snd_pcm_recover) underrun occurred

$ emerge -pv qemu alsa-lib

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild   R    ] media-libs/alsa-lib-1.1.4::gentoo  USE="python -alisp -debug -doc" PYTHON_TARGETS="python2_7" 0 KiB
[ebuild   R    ] app-emulation/qemu-2.9.0-r54::gentoo  USE="aio alsa bzip2 curl fdt gnutls jpeg lzo ncurses nls opengl pin-upstream-blobs png python sdl seccomp usb vhost-net -accessibility -bluetooth -caps -debug -filecaps -glusterfs -gtk -gtk2 -infiniband -iscsi -nfs -numa -pulseaudio -rbd -sasl -sdl2 (-selinux) -smartcard -snappy -spice -ssh -static -static-user -systemtap -tci {-test} -usbredir -vde -virgl -virtfs -vnc -vte -xattr -xen -xfs" LINGUAS="-bg -de_DE -fr_FR -hu -it -tr -zh_CN" PYTHON_TARGETS="python2_7" QEMU_SOFTMMU_TARGETS="i386 x86_64 -aarch64 -alpha -arm -cris -lm32 -m68k -microblaze -microblazeel -mips -mips64 -mips64el -mipsel -moxie -nios2 -or1k -ppc -ppc64 -ppcemb -s390x -sh4 -sh4eb -sparc -sparc64 -tricore -unicore32 -xtensa -xtensaeb" QEMU_USER_TARGETS="-aarch64 -alpha -arm -armeb -cris -hppa -i386 -m68k -microblaze -microblazeel -mips -mips64 -mips64el -mipsel -mipsn32 -mipsn32el -nios2 -or1k -ppc -ppc64 -ppc64abi32 -ppc64le -s390x -sh4 -sh4eb -sparc -sparc32plus -sparc64 -tilegx -x86_64" 0 KiB


This is an automated cleanup. This bug report has been moved
to QEMU's new bug tracker on gitlab.com and thus gets marked
as 'expired' now. Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/69