Problem with broken sound on some ThinkPads
Information about the phenomena of broken sound on 600/E type ThinkPads.
Contents
Problem description
The following is not true with a Fedora Core Devel kernel 2.6.10-1.1109_FC4 (and probably other kernels) on IBM ThinkPad 600X machines. Just use the CS4610 drivers and sound will work fine. Trent Jarvi, tjarvi at qbang.org
First of all, be aware that even though the sound chip is a Crystal SoundFusion 4610, you'll have to use the cs4236 driver to enable sound on this machine, since this driver supports the CS4239 emulation that the 4610 chip offers.
Done that you might experience the phenomena that your sound goes into a loop after about a second just like a scratched record.
Affected Models
Affected Operating Systems
- Linux, all flavours
Status
The PCI chip that you see in lspci (in my 770x case 4610) is the DSP half of the soundcard. You also need a codec to do conversion between digital and analog, audio routing, etc. The CS46xx driver expects to find an AC'97-compatible chip addressible through the PCI Cirrus logic chip to do these tasks.
However, in the affected laptops there is no AC'97 chip. Instead there is an older, ISA-based soundcard to do these tasks as well as providing legacy app support. The cs46xx driver cannot find the AC'97 chip, nor can it support the ISA soundcard for codec duties, so closes finding no soundcards. The current solution is to ignore this PCI chip and use sound though the legacy ISA chip only, either through the cs4236 or cs4232 driver.
Alternatively, I have tried removing the dependency on the existence on a AC'97 codec in the cs46xx driver, theory being that it may be possible to use the cs4236 driver for the mixing functions. This resulted in the driver loading and detecting all the resources of the cs4610, however interrupt issues seemed to be preventing it from outputting sound.
A good thread on the problem can be found in the alsa-devel mailing list
Here's an older explanation of what happens:
The problem with the 600 series is that there is not one, not two, but THREE chips that look like sound cards to Linux. The actual Crystal chip is one of them, the mwave is another, and the video chipset has a DSP that can be used as sound circuitry if a designer opted to do so.
Solutions
Solution #1
Compile the sound driver as module and load it after everything else. You can create a boot script with the following line for that:
/sbin/modprobe snd-cs4236 index=0 port=0x530 cport=0x538 irq=5 dma1=1 dma2=0 isapnp=0
This is reported to work at least with kernel 2.6.9.
If the above line fails, quick boot is probably activated in the bios. In that case you need to manually activate the sound card:
- With apm and pnpbios, this is done with setpnp from the pcmcia package:
# setpnp 0x0e on&& setpnp 0x0f on - With acpi and pnpacpi, the command is:
# echo 'activate' >/sys/devices/pnp0/00:05/resources && echo 'activate' >/sys/devices/pnp0/00:06/resources
This only works with a kernel that fully supports pnpacpi, and provided that this patch has been applied. It seems that the dma numbers change with pnpacpi (dma1=1, dma2=5 for instance).
Solution #2
Make sure that the bios quick boot feature is disabled.
Add the following lines to one of your init process files, i.e, rc.local:
modprobe sound insmod ad1848 insmod uart401 insmod cs4232 io=0x530 irq=5 dma=1 dma2=0
Solution #3
If your module loads like it should, but audio loops or sounds choppy then reloading module should help:
# rmmod cs4232 && modprobe cs4232
