[PlanetCCRMA] rebuilding alsa for edge kernel

Fernando Lopez-Lezcano nando@ccrma.Stanford.EDU
Mon Jul 25 18:24:01 2005

On Mon, 2005-07-25 at 18:06, Hector Centeno wrote:
> Fernando Lopez-Lezcano wrote:
> >On Sat, 2005-07-23 at 11:36, Hector Centeno wrote:
> >>I just successfully rebuilt the alsa-driver and alsa-kernel for the 
> >>2.6.10-2.1.ll.rhfc3.ccrma. I had to do it in order to include a patch 
> >>that allows me to use my USB keyboard (Miditech Midistuido-2). I 
> >>downloaded the alsa source rpm from the CCRMA repository and everything 
> >>worked fine (I uninstalled the default Kernel-module-alsa for installing 
> >>the new compiled alsa-kernel). Now I'm trying to do the same for the 
> >>last edge kernel (0.21) following the same procedure but is not working. 
> >>Even though I recompiled the alsa-kernel, at boot it complains about 
> >>unknown symbols. If I uninstall the rebuilt kernel 
> >
> >You mean "kernel-module-alsa-...", right?
> >
> >>and reinstall the 
> >>official one everything works fine. Is there a different procedure to 
> >>follow for building the alsa-kernel for the edge kernels? Do I need a 
> >>different alsa-driver.spec file?
> >
> >No, the same one should work for both kernels. Are you booting into the
> >edge kernel when you rebuild the rpm? Otherwise you have to tell the
> >spec file which kernel you are building on:
> >
> ># kernel version:           --define "kernel_version VERSION_TO_USE"
> >
> >But if you are running the edge kernel the spec file should pick up the
> >right kernel version. Are you using the right target cpu? (either
> >"--target i686" or "--target i586", has to correspond to the
> >architecture of the kernel you have installed. 
> >
> I managed to make alsa work with the necessary patches under kernel 
> 2.6.12-0.21. Now I can get a latency as low as 11ms with no xruns at all 
> with my USB Duo, which is very good! (with the 2.6.10 I was getting 23ms 
> and some xruns). Now that I'm not loading the MPU401 module, and I'm 
> using my keyboard through the USB port, the system is stable (that was 
> the cause of my system freezing as it seems that the mpu401 port 
> included in the intel8x0 is not very stable). In order to get alsa to 
> work I didn't install or recompiled any kernel-module-alsa. What I did 
> is to apply the patches to the alsa code included inside the kernel 
> source and recompile the kernel.
> What version of alsa is included inside the 2.6.12-0.21 kernel? 

Whatever comes with stock 2.6.12...

> What is 
> the difference between using the alsa modules included in the kernel and 
> installing the kernel-module-alsa.2.6.12-0.21? 

kernel-module-alsa is normally more up to date than what is included in
the kernel itself. 

> Does installing the 
> second one overrides the alsa modules included in the kernel? I don't 
> really understand what is the purpose of having the kernel-module-alsa 
> as a separate rpm.

Yes, it does override the alsa kernel modules in the kernel. In this way
it is possible to update alsa without having to update the kernel (which
is more complicated). Alsa as available on the alsa-project.org, either
latest stable release or cvs is more up to date than what makes it to
the stable kernel tree. 

-- Fernando