#emc-devel | Logs for 2006-06-11

[13:13:42] <brokenthorn> alex_joni, I'm here
[13:13:59] <alex_joni> hello
[13:14:04] <brokenthorn> Hi
[13:14:09] <alex_joni> reading the -beyond stuff
[13:14:22] <brokenthorn> Yes, that's a good patchset
[13:14:31] <brokenthorn> I want to tailor my system for the desktop
[13:14:48] <alex_joni> I heard stuff about it, but I thought it's still kinda far away from switching latencies we need
[13:14:50] <brokenthorn> And I don't mean the usual desktop ;)
[13:15:17] <alex_joni> kinda guessed that ;)
[13:15:23] <brokenthorn> I don't know about the latencyies because I'm trying it today
[13:15:48] <alex_joni> brokenthorn: the thing is that we use RT to output stepper pulses (for motor control), so it's kinda critical
[13:16:03] <alex_joni> if the pulses don't arrive when they should, the motor WILL stall
[13:16:03] <brokenthorn> Yes... I've seen the project
[13:16:19] <brokenthorn> Pretty interesting :D
[13:16:26] <alex_joni> not always stepper output, but that's the most problematic
[13:16:32] <brokenthorn> Fascinating ;)
[13:17:06] <brokenthorn> But I want a real-time kernel, or as much as it gets
[13:17:06] <alex_joni> and the problem is to have it ALWAYS reliable.. not 99% of the time
[13:17:22] <alex_joni> well, the RTAI stuff takes a different approach
[13:17:24] <brokenthorn> And you run Ubuntu on the machine?
[13:17:34] <alex_joni> it basicly installs underneath the linux
[13:17:43] <alex_joni> and runs when it should :)
[13:17:53] <alex_joni> gives control back to the kernel when it's idle
[13:17:56] <brokenthorn> Hm... doesn't sound like me
[13:17:58] <alex_joni> brokenthorn: yes, Ubuntu
[13:18:02] <brokenthorn> I want it to 'run' all the time
[13:18:31] <brokenthorn> And what happens to the usplash?
[13:18:37] <alex_joni> this happens usually very fast (few usecs), so you don't notice it
[13:18:41] <brokenthorn> Do you still have that?
[13:18:52] <alex_joni> brokenthorn: usplash stays black when I tried to install a custom one
[13:18:57] <alex_joni> the default one works ok
[13:19:10] <brokenthorn> Did RTAI patch the kernel?
[13:19:23] <alex_joni> they provide patches, yes
[13:19:28] <brokenthorn> Did you made a config based on the stock kernel's one?
[13:19:36] <alex_joni> brokenthorn: right
[13:19:50] <brokenthorn> So usplash is userland
[13:20:19] <alex_joni> all linux is userland
[13:20:24] <brokenthorn> What does it need in the kernel to work? vesafb-tng and fbconsole ?
[13:20:27] <alex_joni> only specific coded parts are RT
[13:20:37] <alex_joni> fbcon & vesa16fb I think
[13:20:45] <brokenthorn> vesa16? :O
[13:20:52] <alex_joni> but the RT part is way later, after the system booted
[13:20:58] <alex_joni> yup, that's the ubuntu default
[13:21:02] <brokenthorn> :-/
[13:21:19] <brokenthorn> Why not vesafb?
[13:21:24] <brokenthorn> it's the latest best
[13:21:31] <brokenthorn> :-
[13:21:37] <alex_joni> dunno, probably ubuntu people decided 16 is more spread?
[13:21:44] <brokenthorn> No way
[13:21:46] <brokenthorn> Anyway
[13:21:53] <alex_joni> not my call :)
[13:22:00] <brokenthorn> did you lose the initrd?
[13:22:05] <alex_joni> no
[13:22:10] <brokenthorn> so you still use that
[13:22:19] <alex_joni> it's needed for fbcon afaik
[13:22:46] <brokenthorn> I decided not to use it and it can't mount the root partition
[13:22:55] <brokenthorn> I get a kernel panic at boot
[13:23:25] <brokenthorn> What kind of machine does Ubuntu run on?
[13:24:25] <alex_joni> any x86 fwiw
[13:26:33] <jepler> ubuntu also runs on at least pcc and x86_64, but there's no realtime kernel built for them.
[13:26:33] <jepler> er, ppc
[13:27:22] <brokenthorn> No, I was wondering about the kernel config you use
[13:27:22] <brokenthorn> I don't know what to keep not to break any ubuntu compatibility
[13:27:22] <brokenthorn> did you patched a vanilla kernel?
[13:27:24] <brokenthorn> because the kernel in the repos have lots of ubuntu patches
[13:27:26] <brokenthorn> I wonder if it's going to break something
[13:27:30] <brokenthorn> I don't have those arch's I have i686 (pentium 4 2.4GHz)
[13:28:05] <brokenthorn> I need to know if using a patched vanilla kernel with the -beyond patchset or any patchset will break ubuntu!!!
[13:28:45] <alex_joni> brokenthorn: I used the ubuntu sources
[13:28:57] <alex_joni> and tiny tweaked the rtai patches
[13:29:07] <alex_joni> but you'll be best asking in #ubuntu-kernel
[13:29:15] <brokenthorn> thanks
[13:29:39] <jepler> I must have missed the beginning of this conversation. What is "the -beyond patchset"?
[13:31:05] <brokenthorn> http://members.optusnet.com.au/ckolivas/kernel/
[13:31:12] <alex_joni> jepler: some patch to improve latency on a default kernel
[13:31:24] <alex_joni> not much documentation though
[13:31:28] <brokenthorn> jepler, Look at "Other interesting links"
[13:34:36] <jepler> thanks, reading
[13:36:05] <alex_joni> this also has some relevance: http://freequaos.host.sk/schedtool/
[13:36:17] <alex_joni> but I think it's still pretty far away from what we need
[13:43:49] <skunkworks> wouldn't you want the rt kernel even for servo cards? or are the computers fast enough now?