Re: Report of install for a power6 with debian-squeeze-di-beta1-powerpc-netinst.iso
Hello,
On Wed, Dec 08, 2010 at 10:50:15PM +1100, Anton Blanchard wrote:
> It's not specific to Linux, however it may be more obvious because we
> have an extra step with yaboot.
>
> The kernel communicates to firmware via the
> ibm,client-architecture-support call. This call allows us to tell
> firmware about all the various features we support. Unfortunately when
> we ask for something different than the previous boot firmware is
> often past the point of no return and has to reboot and reconfigure.
>
> As an example, I recently added support for a more detailed NUMA
> topology feature:
>
> http://patchwork.ozlabs.org/patch/49682/
>
> Since this feature changes the meaning of some parts of the Open
> Firmware device tree, when firmware see this field change between boots
> it has no option but to reboot and reconfigure the device tree it
> presents.
>
> yaboot has code to recognise this reboot and to retry the previous
> kernel automatically and without delay. So bottom line is we should
> expect double booting when going between AIX and Linux or sometimes
> between versions of Linux (eg a kernel before and after my NUMA change).
>
> If we are seeing the partition continually go around in a loop due to
> the client architecture then that is a bug.
thanks for taking the time to explain! I wasn't referring to a setup
where i switch between AIX and Linux in the same LPAR though, but in-
stead having different LPARs with different OSes that seem to behave
differently. E.g. on a reboot and/or poweroff/poweron of a AIX LPAR i
see no double boot on the vterm, even if i purposely change the LPARs
virtual hardware configuration (e.g. add a veth). With Linux i had the
occasional case where i reboot, SMS banner goes by, yaboot prompt comes
up, yaboot loads, reset to yaboot prompt again and then it stays there
not trying another boot until you manually tell it what bootlist entry
to load, then it starts up fine, even if the bootlist entry entered is
exactly the same it tried the first time. Sounds odd, i know. Sadly i
haven't had the time to figure out a reproducable case.
Btw. is there a way to tell yaboot to be a bit more verbose without
having to rebuild the whole thing with "DEBUG=1"?
Thanks & best regards,
Frank
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