My Linux 2.5 Trials and Tribulations

I'm going to document my tinkerings with the new Linux 2.5 kernel series (see www.kernel.org) here. It won't be anything official, just a collection of notes. I've made the effort of writing it in HTML for you all though, to make the link clicking a little easier I guess.

It starts here with version 2.5.54. I have recompiled a few times throughout this testing which will certainly skew any bug reports based on this information alone, so be aware.

Ximian Evolution

Evolution stopped working properly when I moved to 2.5.54 but I found a patch to fix what seems to be a bug in ORBit. I believe the getpeername syscall in 2.4 was slightly broken and ORBit relied on the broken behaviour. 2.5 fixed it and ORBit broke.

I have built i386 RPMS of ORBit, including this patch.

ACPI

My Dell Inspiron 8200 spikes to 100% CPU when gnome battstat-applet reads the battery status. I had similar problems with an Inspiron 4000 with 2.4 so I assume it's a lame hardware implementation. I'll check into it further soon.

APM

I am truly amazed by the apm support so far. I can fully suspend and wake-up my laptop without the usual problems i.e: corrupted display, X crashing, dead network cards, dead sound cards, hardware freezing, rebooting (in actual fact, I've never even had a successful suspend on *any* apm "compliant" hardware with any Linux, EVER! Until now...

USB

Module kernel panic

Inserting the hid kernel module into a kernel with hid statically compiled in causes a kernel panic. (NULL pointer dereference). My colleague thinks this may be related to the define init code. I need to confirm this and report it.

RedHat 8.0 initscript incompatabilities

The RH8 initscripts try to insert the keyboard and mouse input layer modules which, as far as I can see, don't come as modules any more.
The RH8 initscripts also mount /proc/bus/usb as usbdevfs, which is depricated in favour of usbfs.
I get the following message in my kernel log: "warning: process `update' used the obsolete bdflush system call Fix your initscripts?". The '/sbin/update' binary, from the bdflush package, seems to be causing this. Don't know what the alternative is yet.
I've fixed these little changes manually, but may make an rpm and make it available here soon.

Modules

None of my kernel modules automatically load. I need to "migrate" my modules.conf. More details when I do so.

Mouse

I changed my XFree86 config to use the /dev/input devices now instead of /dev/psauxf (even though this device is still available under 2.5. This is in the hope that I won't need to change my mouse preferences each time I change from mouse to touchpad (I'm hoping the resolutions will be detected or something). More details soon.

CPU Frequency Scaling

My Mobile P4 seems to frequency scale just perfectly now (although given the option, "P4/Xeon(TM) CPU On-Demand Clock Modulation" gets chosen over Speedstep, which I thought was the default on my CPU (Intel(R) Pentium(R) 4 Mobile CPU 1.60GHz).

Cpufreqd seems to do a nice job of monitoring my battery via apm and changing the scaling policy dynamically. I wrote a RedHat 8 init script for it (as requested in the TODO file) based on the RedHat APMD script.

Burning/Ripping CDs

Ripping seems faster, but this is a subjective analysis. I've witnessed ripping speeds up to double the fastest speed I've ever achieved on a 2.4 kernel, although I'm never in enough of a hurry to need to rip CDs so I don't spend a lot of time tweaking and testing.

During the tests cdda2wav was using less than 1% user cpu, and 30% system (on a 1.6Ghz P4 reaching ripping speeds of 8x). I used the cdda2wav tools from FIXME

I will do some cdburning tests as soon as I find my laptop CD writer. I believe it is in the excessively pocketed laptop bag Dell kindly supplied to me for "free (ie: an absorbed cost). UPDATE: It was in the bag. Not done any tests yet though.

Weirdness and "issues"

Sometimes after a warm reboot, I get about 2 lines into the initial kernel boot process and my laptop just powers right off suddenly. UPDATE: I also eXPerience the power-off whilst booting XP (yaick) after rebooting Linux.
Whilst compiling, my mouse jerks around and running any other task isn't much fun until the compile finishes. UPDATE: If I switch to the console, all is well. No jerkyness, no lag, no problems. It has been suggested that this behaviour could be attributed to the new scheduler, which flags high CPU processes as background processes after a while, therefore they can get a little unresponsive. I suppose I could run X with the nice commend and set it as high priority. I wonder what the developers are going to do about this.
grip-3.0.1-4, I can only assume due to polling the cdrom drive in some way, produces end_request: I/O error, dev hdb, sector 0 messages in my kernel logs.
The Nvidia framebuffer driver doesn't work for my GeForce2 GO card. According to the source it is supported, but booting with vga=796 just produces what looks like 4 copies in the screen, with green lines through it. Sticking to the VESA one for now.

Last updated Monday 13 January 2003
Copyright (c) John Leach <john at johnleach dot co dot uk >