[ubuntu-x] PowerPC bugs

Colin Watson cjwatson at ubuntu.com
Thu Oct 4 13:25:39 UTC 2012

On Thu, Oct 04, 2012 at 01:53:32PM +0100, o jordan wrote:
> Is it too late to get some PowerPC changes into the yaboot options on
> the live/desktop ISOs?
> I have an idea to build back in the legacy nvidia framebuffers into
> the PowerPC kernel.  Whilst this is a backwards step in many respects,
> it is the only way (I can think of) to get over the 16 colour
> limitation of the openfirmware framebuffer.  Currently if you turn off
> kernel modesetting with nouveau (and this it seems is a necessity now
> for many cards of some vintage) you are thrown into a desktop with
> only 16 colours on PowerPC and this is a largely unusuable desktop.
> As this kernel change will disable KMS (which we don't want to do for
> every nvidia card) the boot options need updating so that the legacy
> framebuffers are turned off by default:
> video=radeonfb:off video=rivafb:off video=nvidiafb:off  
> Since you cannot easily remove default yaboot parameters a new
> 'failsafe' option would need to be created on the desktop ISO without
> these parameters.  This could replace the 'nosplash' option.  The new
> yaboot parameters would be: nomodeset vt.handoff=7 I know you don't
> think vt.handoff=7 makes any sense with yaboot, but it does actually
> boot you into a higher colour depth than you would without it.  This
> solves the problem of the installer windows not appearing in 8 bit
> pseudo colour. I think I can create a patch for yaboot-installer (to
> also introduce a failsafe option on an installed system), but I have
> no clue what files are involved in the creation of the ISOs.  If you
> can point me in the right direction then I can take (a rather
> uneducated) look at them and see if I can come up with the necessary
> changes myself. Of course this all depends on getting the PowerPC
> kernel changed, something that I have struggled to do in the past.
> Like yourself they are very cautious about changes.  I would need help
> from somebody within Canonical to support the kernel change. These
> changes would not improve the out-of-the box everything working 100%
> on the first boot support of the PowerPC port (that can only come from
> the kernel/radeon/nouveau developers), but the creation of a failsafe
> mode would make the radeon and nvidia user experience much better.

To be honest, as I think I said before: I'm not going to touch these
options at all without review from the kernel and X teams (CCed).  If
they say it's necessary, then sure; but I would rather that somebody
first checked whether this is a consequence of a bug we can fix, because
it's always better for the software to work by default than to require
boot parameters.


Colin Watson                                       [cjwatson at ubuntu.com]

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