Audio in Lenovo T400

Audio in Lenovo T400

[ghi]

Hi,
I've bought Lenovo Thinkpad T400 to run 9front on it. The only pice of 
hardware that is not working right now is audio device. I've tested it 
with play(1) and some ogg file and I can hear no sound. Master in 
/dev/volume is set to 100 so i believe that i should hear something.

Now I have several questions regarding this problem.

1. Where are audio devices drivers stored? I believe that in 
/sys/src/9/pc but I'm not fully certain.

2. How I can test audio card to be sure that this is a driver problem.

3. Which file use as a template for new audio driver? And how to setup 
driver development envirmoent(can i load drivers into kernel without 
restarting machine? how to test and compile the driver?)

BR
ghi

Re: [9front] Audio in Lenovo T400

[cinap_lenrek]

> 1. Where are audio devices drivers stored? I believe that in 
> /sys/src/9/pc but I'm not fully certain.

intel hd audio driver source is /sys/src/9/pc/audiohda.c, which
gets called by by /sys/src/9/port/devaudio.c

> 2. How I can test audio card to be sure that this is a driver problem.

you probably just need to set the right output pin in /dev/audioctl

> 3. Which file use as a template for new audio driver? And how to setup 
> driver development envirmoent(can i load drivers into kernel without 
> restarting machine? how to test and compile the driver?)

you can pick any /sys/src/9/pc/audio*.c as a template. the plan9
kernel does not have loadable kernel drivers. kernel drivers are
build into the kernel and require a new kernel to be build
and a reboot after a change them to test. vga drivers and usb
drivers are just normal userspace programs tho. so not all driver
development requires a kernel driver.

i have a bunch of plan9 machines running, so for driver development,
i just netboot the machine with the hardware with my development
kernel.

plan9 kernel is quite simple, you should have no problem figuring
it out by looking at the other drivers. the kernel you build is
build from a configuration file, /sys/src/9/pc/9pcf is build from
/sys/src/9/pc/pcf for example. this file contains the list of
drivers that get build into it. there are two types of kernel
drivers:

dev: which export a Dev structure with function pointers to
implement a (kernel) fileserver, they are all named dev*.c.

link: which just export a <nameofdriver>link() function
that gets called early on boot. the audio and ethernet drivers are
of this kind. they do not implement the device fileservice directly
but just register themselfs in ther link function with a dev.

you build a kernel with mk. mk 'CONF=confname' to build a kernel
of a specific configuration. gives you 9confname kernel image.

--
cinap

Re: [9front] Audio in Lenovo T400

[ghi]

> plan9 kernel is quite simple, you should have no problem figuring
> it out by looking at the other drivers. the kernel you build is
> build from a configuration file, /sys/src/9/pc/9pcf is build from
> /sys/src/9/pc/pcf for example. this file contains the list of
> drivers that get build into it. there are two types of kernel
> drivers:
>
> dev: which export a Dev structure with function pointers to
> implement a (kernel) fileserver, they are all named dev*.c.
>
> link: which just export a <nameofdriver>link() function
> that gets called early on boot. the audio and ethernet drivers are
> of this kind. they do not implement the device fileservice directly
> but just register themselfs in ther link function with a dev.
>
> you build a kernel with mk. mk 'CONF=confname' to build a kernel
> of a specific configuration. gives you 9confname kernel image.
Thank you for explaining that. The Plan 9 has again charmed me with it's 
simplicity.

BR
ghi