[plug] Frustration

Lyndon Maydwell maydwell at gmail.com
Fri Sep 7 13:11:09 WST 2012

> I wonder if I can install xmonad in OSX ??

You can, but obviously only under X11 on OSX. It's not really worth it.

On Fri, Sep 7, 2012 at 12:45 PM, Brad Campbell <brad at fnarfbargle.com> wrote:
> Sometimes I wonder why I stick with Linux....
> I have a 2011 iMac. It has a Radeon card in it. The machine has two external
> display ports.
> When I bought the machine, I bought a 27" cinema display with it and also
> connected up my old 24" DVI monitor.
> I spent 3 days hacking the kernel radeon driver to try and figure out why it
> refused to drive the cinema display over the thunderbolt port.
> Got that fixed to find out when you install Linux and have one or more
> external monitors connected, the kernel radeon driver clocks the card up to
> full throttle and attempts to cook the machine.
> So spent another couple of hours with my head in the driver to figure out a
> way to effectively clock it down. Developed a nasty hack which did the job.
> Fast forward 12 months. Upgraded to kernel 3.4.10 to find that my machine
> would panic on logging into X. Spend 6 hours bisecting back to a patch added
> in 3.4.8 which was fundamentally broken. Notified the maintainer to get "oh
> yeah, I have a revert queued up for that". It's only been broken for 2
> stable releases.
> Get that fixed to find noise artefacts on the screen now. Bisect that back
> to another patch by the same maintainer. Asked him about it and got "Running
> more than one head in the low power profile is unsupported". No shit
> sherlock, that's why I've been carrying a nasty hack for 12 months. Run in
> an unsupported mode or have the machine sound like a 747 trying to keep the
> card from bursting into flames.
> So, let's spend another 8 hours tracking through the Radeon driver to try
> and figure out why the power management is broken. Have a quick google...
> oh, lots of people with the same complaint "kernel radeon driver makes my
> laptop overheat and shut down". Standard maintainer answer is "you'll need
> to manually fiddle the clock values", but no information on how that might
> be achieved.
> Turns out the radeon BIOS has a set of power profiles programmed into it by
> the maker. There is even a sane way to parse them in the radeon driver, but
> rather than make it configurable or switchable it is hardcoded to use a
> certain profile type.
> In my case, the Radeon in my iMac is a mobile radeon. The radeon driver says
> if its a mobile chip then select the battery profile. If you are running
> multi-head mode then select the second battery profile. Oh! What's that you
> say? You don't have a second battery profile? Right then let's default to
> the profile we can find with the highest power dissipation and use that for
> all our configurable power settings (high, mid, low).
> A quick hack to the driver to use the "battery" profile (which is the lowest
> power dissipating setting), and then a kernel module parameter to allow me
> to set the minimum GPU clock and Memory clock values, and I can now tweak
> the GPU clock up a couple of MHZ and the display noise goes away.
> So, now I see the kernel has a misc usb driver than allows control of an
> external apple monitor. No worries, I've already patched acdcontrol to
> control the backlight on my cinema display, so let's patch the in-kernel
> driver so I can use /sys/class/backlight/* to control both monitors. Yay!
> Spend a couple of fun hours hacking that up to find that
> gnome-power-manmager and hal both shit the bed if there is more than one
> backlight device. Each backlight has a different resolution. The built in
> device has 4 bits of brightness, while the cinema display as 16. So gnome
> power manager gets confused by this and ties itself in a knot.
> I wonder if I can install xmonad in OSX ??
> _______________________________________________
> PLUG discussion list: plug at plug.org.au
> http://lists.plug.org.au/mailman/listinfo/plug
> Committee e-mail: committee at plug.org.au
> PLUG Membership: http://www.plug.org.au/membership

More information about the plug mailing list