Linux Archive - Fw: where is: linux-headers-2.6.29-1-common-multimedia

Mathias Krause wrote:
>> And because of the sources, I run Synaptic and saw that there aren't the
>> common headers in the amd64 repository. In any case I guess it is good
>> to compile the latest kernel and to add latest rtirq, when there's the
>> need to build the graphics module ... not generally, but at the moment
>> there seems to be a big step for the real-time kernel (and rtirq).
>>
>
> That's an important thing i did not yet understand. What is the difference
> between the kernel-multimedia-amd64 and rt19-20100103? When looking at the
> naming of that kernels, the last one seems that rt19 has nothing todo with
> multimedia ... and the rt kernel seems to be to be more a snapshot, then a
> tested version.... (and remember, i got that rt19 kernel from a privat
> repository, not from the official one...)
>

There is the basic kernel, called vanilla kernel, it has got a major
number, e.g. 2.6.31 and a minor number e.g. .6.

You can get the source for 2.6.31 and a patch .6 separated or the
complete source 2.6.31.6.

For real-time you need an additional patch, e.g. -rt19. The complete
name than will be 2.6.31.6-rt19.

Older patches are available here:
http://www.kernel.org/pub/linux/kernel/projects/rt/older/

I build a kernel 2.6.31.6-rt19 for my 64 Studio. The patch needs to be
especially for the kernel version. The actual one is
patch-2.6.31.12-rt20, this means patch -rt20 is the micro number and the
patch is only for kernel 2.6.31.12, available at
http://www.kernel.org/pub/linux/kernel/projects/rt/.

Today it's common only to use this rt patches and I'm nearly sure the 64
Studio guys are using it too. In the past there were 2 different patches
common.

Anyway, even similar kernel versions, using the same patch could have
different configurations.

spinymouse-sudo@64studio:~/Desktop$ ls /boot/config*
/boot/config-2.6.29-1-multimedia-amd64
/boot/config-2.6.29.3-rt13-suspend2 /boot/config-2.6.31.5-rt18
/boot/config-2.6.31.6-rt19

I could build a new kernel 2.6.31.6-rt19, but with another configuration
and call it e.g. 2.6.31.6-rt19-2010Feb06.

For example, there is a snd-hrtimer module, that did exist for 2.6.29
kernels and it exists also for 2.6.31 kernels. The multimedia kernel
isn't configured with it.

spinymouse-sudo@64studio:~/Desktop$ cat
/boot/config-2.6.29-1-multimedia-amd64 | grep CONFIG_SND_HRTIMER
# CONFIG_SND_HRTIMER is not set
spinymouse-sudo@64studio:~/Desktop$ cat /boot/config-2.6.31.6-rt19 |
grep CONFIG_SND_HRTIMER
CONFIG_SND_HRTIMER=m
spinymouse-sudo@64studio:~/Desktop$

You also could build a kernel 2.6.29-1-multimedia-amd64 with, resp. a
kernel 2.6.31.6-rt19 without this option. Even if SND_HRTIMER is more
experimental than the real-time patch already is, you don't need to load
and use the module, so it doesn't have impact to the stability of the
kernel.

But for example the number of CPUs could have impact.

spinymouse-sudo@64studio:~/Desktop$ cat
/boot/config-2.6.29-1-multimedia-amd64 | grep CONFIG_NR_CPUS
CONFIG_NR_CPUS=512
spinymouse-sudo@64studio:~/Desktop$ cat /boot/config-2.6.31.6-rt19 |
grep CONFIG_NR_CPUS
CONFIG_NR_CPUS=2

While CONFIG_NR_CPUS is set up to 512, there shouldn't be trouble, when
using a quad-core CPU, but when the value is 2, I guess there could be
trouble.

A new kernel and a new rt patch are less proved than older once, but the
new once are the latest releases and they aren't just snapshots for
testing only.

Differences will be because of different kernel versions and because of
the configuration, but for same kernel versions differences aren't
because of snapshot developer directory versions, but only because of
configurations, or because there are additional patches, e.g. because of
an additional patch for a special kind of suspend function.

For the distro there could be dependencies too, e.g. if you'll use a
kernel 2.6.31.6-rt instead of a kernel 2.6.29-1-multimedia =
2.6.29.x-rt, you also need latest rtirq script, because of changes for
setting up preemtion/real-time values.

You need to ask Quentin about possible "special configurations" or
additional patches, but I'm sure his kernel is a preemtion/real-time
kernel and I'm nearly sure that the multimedia kernel don't comes with
additional patches, but the regular rt patch.
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