Booting headless PowerMac G5

Booting headless PowerMac G5

[Romain Goyet]

Hi there,


  Here's a summary about "how to boot a PowerMac G5 without a screen
attached". As many people have noticed, default yaboot install won't
boot unless a screen is attached.

  Actually, the workaround is really simple. Thing is, that's the
"ofboot.b" script that messes things up. This script is a "bridge",
that actually either starts yaboot or let you boot off of a CD. I
don't know what's the point, since OpenFirmware already lets you boot
off of the CD by pressing C on boot=E2=80=A6

  So basically, to boot headless, all you have to do is to tell
OpenFirmware to boot straight off the yaboot binary, and to skip the
ofboot.b
Just boot into OpenFirmware (Command-Option-O-F), and type :
setenv boot-device hd:2,yaboot (where 2 is the number of the partition
containing yaboot)
boot

And here you go, you can unplug that useless monitor :-)

References :
http://saintaardvarkthecarpeted.com/blog/archive/2005/02/THE_WINE_OF_BOOT.h=
tml
http://grub.enbug.org/TestingOnPowerPC

By the way, as of writing this, grub2 on PPC from debian gives a "out
of memory" issue. Known bug.

Re: Booting headless PowerMac G5

[Benjamin Herrenschmidt]

On Wed, 2010-03-24 at 11:32 +0100, Romain Goyet wrote:
> Hi there,
> 
> 
>   Here's a summary about "how to boot a PowerMac G5 without a screen
> attached". As many people have noticed, default yaboot install won't
> boot unless a screen is attached.

CC'ing Tony who is the latest victim of yaboot maintainership...

>   Actually, the workaround is really simple. Thing is, that's the
> "ofboot.b" script that messes things up. This script is a "bridge",
> that actually either starts yaboot or let you boot off of a CD. I
> don't know what's the point, since OpenFirmware already lets you boot
> off of the CD by pressing C on boot…
> 
>   So basically, to boot headless, all you have to do is to tell
> OpenFirmware to boot straight off the yaboot binary, and to skip the
> ofboot.b
> Just boot into OpenFirmware (Command-Option-O-F), and type :
> setenv boot-device hd:2,yaboot (where 2 is the number of the partition
> containing yaboot)
> boot
> 
> And here you go, you can unplug that useless monitor :-)

The root of the problem is that Apple OF will not open an stdout for you
on some machines if you don't enter OF manually, so yaboot text never
shows up. This was somewhat worked around by the ofboot.b script but
indeed, it seems to fail to check that there's a display to open before
actually opening it, which cause the failure you are hitting.

Maybe we can try to make the script a bit smarter to detect that there's
nothing there. Hard to tell, the arcanes of Apple OF are quite obscure.

But at least, I think ybin could grow a config option to tell it not to
install ofboot.b or at least install a variant that won't suck when
there is no display attached.

Cheers,
Ben.

> References :
> http://saintaardvarkthecarpeted.com/blog/archive/2005/02/THE_WINE_OF_BOOT.html
> http://grub.enbug.org/TestingOnPowerPC
> 
> By the way, as of writing this, grub2 on PPC from debian gives a "out
> of memory" issue. Known bug.
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev

Re: Booting headless PowerMac G5

[Segher Boessenkool]

> The root of the problem is that Apple OF will not open an stdout  
> for you
> on some machines if you don't enter OF manually, so yaboot text never
> shows up. This was somewhat worked around by the ofboot.b script but
> indeed, it seems to fail to check that there's a display to open  
> before
> actually opening it, which cause the failure you are hitting.

Check /chosen/stdout , if it's there and non-zero there is an open
output device (whether some screen or serial or telnet or whatever).
This is an ihandle.

> Maybe we can try to make the script a bit smarter to detect that  
> there's
> nothing there. Hard to tell, the arcanes of Apple OF are quite  
> obscure.

I'll check them all (well, anything in the NewWorld) if you tell me
what to check.


Segher

Re: Booting headless PowerMac G5

[Michel Dänzer]

On Wed, 2010-03-24 at 11:32 +0100, Romain Goyet wrote:=20
>=20
>   Here's a summary about "how to boot a PowerMac G5 without a screen
> attached". As many people have noticed, default yaboot install won't
> boot unless a screen is attached.
>=20
>   Actually, the workaround is really simple. Thing is, that's the
> "ofboot.b" script that messes things up. This script is a "bridge",
> that actually either starts yaboot or let you boot off of a CD. I
> don't know what's the point, since OpenFirmware already lets you boot
> off of the CD by pressing C on boot=E2=80=A6
>=20
>   So basically, to boot headless, all you have to do is to tell
> OpenFirmware to boot straight off the yaboot binary, and to skip the
> ofboot.b
> Just boot into OpenFirmware (Command-Option-O-F), and type :
> setenv boot-device hd:2,yaboot (where 2 is the number of the partition
> containing yaboot)
> boot
>=20
> And here you go, you can unplug that useless monitor :-)
>=20
> References :
> http://saintaardvarkthecarpeted.com/blog/archive/2005/02/THE_WINE_OF_BOOT=
.html
> http://grub.enbug.org/TestingOnPowerPC

That's good to know, thanks.


> By the way, as of writing this, grub2 on PPC from debian gives a "out
> of memory" issue. Known bug.

That's on the G5? It's working on my PowerBook, but I haven't updated
the grub2 binaries on the bootstrap partition in a while...


--=20
Earthling Michel D=C3=A4nzer           |                http://www.vmware.c=
om
Libre software enthusiast         |          Debian, X and DRI developer

Re: Booting headless PowerMac G5

[Romain Goyet]

2010/3/25 Michel D=C3=A4nzer <michel@daenzer.net>:
> On Wed, 2010-03-24 at 11:32 +0100, Romain Goyet wrote:
>>
>> =C2=A0 Here's a summary about "how to boot a PowerMac G5 without a scree=
n
>> attached". As many people have noticed, default yaboot install won't
>> boot unless a screen is attached.
>>
>> =C2=A0 Actually, the workaround is really simple. Thing is, that's the
>> "ofboot.b" script that messes things up. This script is a "bridge",
>> that actually either starts yaboot or let you boot off of a CD. I
>> don't know what's the point, since OpenFirmware already lets you boot
>> off of the CD by pressing C on boot=E2=80=A6
>>
>> =C2=A0 So basically, to boot headless, all you have to do is to tell
>> OpenFirmware to boot straight off the yaboot binary, and to skip the
>> ofboot.b
>> Just boot into OpenFirmware (Command-Option-O-F), and type :
>> setenv boot-device hd:2,yaboot (where 2 is the number of the partition
>> containing yaboot)
>> boot
>>
>> And here you go, you can unplug that useless monitor :-)
>>
>> References :
>> http://saintaardvarkthecarpeted.com/blog/archive/2005/02/THE_WINE_OF_BOO=
T.html
>> http://grub.enbug.org/TestingOnPowerPC
>
> That's good to know, thanks.
>

You're welcome. Actually I also wrote this as a memo for myself :-)

>
>> By the way, as of writing this, grub2 on PPC from debian gives a "out
>> of memory" issue. Known bug.
>
> That's on the G5? It's working on my PowerBook, but I haven't updated
> the grub2 binaries on the bootstrap partition in a while...
>
>


Yeah, that's on a PowerMac QuadG5.
I think that's a known issue :
http://www.mail-archive.com/grub-devel@gnu.org/msg04455.html
However it might be another one since it's working for you. I'm using
grub2 from Debian stable.


> --
> Earthling Michel D=C3=A4nzer =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 | =C2=A0 =
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0http://www.vmware.com
> Libre software enthusiast =C2=A0 =C2=A0 =C2=A0 =C2=A0 | =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0Debian, X and DRI developer
>
>
>
>
>
>

Re: Booting headless PowerMac G5

[Michel Dänzer]

On Fri, 2010-03-26 at 11:20 +0100, Romain Goyet wrote:=20
> 2010/3/25 Michel D=C3=A4nzer <michel@daenzer.net>:
> > On Wed, 2010-03-24 at 11:32 +0100, Romain Goyet wrote:
> >>
> >> By the way, as of writing this, grub2 on PPC from debian gives a "out
> >> of memory" issue. Known bug.
> >
> > That's on the G5? It's working on my PowerBook, but I haven't updated
> > the grub2 binaries on the bootstrap partition in a while...
>=20
> Yeah, that's on a PowerMac QuadG5.
> I think that's a known issue :
> http://www.mail-archive.com/grub-devel@gnu.org/msg04455.html
> However it might be another one since it's working for you. I'm using
> grub2 from Debian stable.

According to http://packages.debian.org/stable/grub2 that's version 1.96
+20080724-16, which is pretty old. Current in sid is 1.98, and it's only
become usable for me in the course of the last year or so.


--=20
Earthling Michel D=C3=A4nzer           |                http://www.vmware.c=
om
Libre software enthusiast         |          Debian, X and DRI developer