[LAU] updates to real-time kernel

[Robin Gareus]

Esben Stien wrote:
> Susan Cragin <susancragin at earthlink.net> writes:
> 
>> It's stuck at 2.6.24-19, and the generic kernel is up to 2.6.26-4
> 
> http://kerneltrap.org/Linux/Removing_the_Big_Kernel_Lock
> 
> It seems like we're stuck with 2.6.25. (I'm stuck with 2.6.23 cause of
> some weird audio problems with xmms2 on 2.6.24 and 2.6.25). 
> 
> Anyone know what the foreseeable future holds?

2.6.24 was very stable for audio, at least over here more so than
2.6.25!   I've got a 2.6.26-rt1 working from
git://git.kernel.org/pub/scm/linux/kernel/git/clrkwllms/rt-linux.git

It supports Rui's rtirq setup and jackd/USB-UA25 ran >5 mins without
xruns at 128frames/period, wifi working, it suspends to RAM and
everything. BUT I did not yet try any longer since it spits out the
following message once per second:

 =======================
BUG: sleeping function called from invalid context swapper(0) at
kernel/rtmutex.c:743
in_atomic():1 [00000001], irqs_disabled():0
Pid: 0, comm: swapper Not tainted 2.6.26-rt1 #2
 [<c01250cb>] __might_sleep+0xeb/0xf0
 [<c034199f>] __rt_spin_lock+0x5f/0x70
 [<c03419b8>] rt_spin_lock+0x8/0x10
 [<c01498d0>] pm_qos_requirement+0x10/0x30
 [<f886afc9>] acpi_processor_idle+0x407/0x530 [processor]
 [<f886abc2>] ? acpi_processor_idle+0x0/0x530 [processor]
 [<c0102cf8>] cpu_idle+0x68/0xf0
 [<c033253c>] rest_init+0x6c/0x70
 =======================

It does not seem to be a real Bug.. but it's an annoying /mosquito/. I
guess it's related to NO_HZ or some ACPI_XXX config. I could not get the
-tip branch to boot at all, but I did not try too hard just yet.

stay tuned,
robin