Re: Booting original iMac

["John D. Baker" <jdbaker%mylinuxisp.com@localhost>]

On Fri, 12 Mar 2010, Michael wrote:

> Or try a -current kernel - it will replay the message buffer when a 
> framebuffer driver attaches.

I'm afraid it doesn't.  I just booted a -current GENERIC (after doing
the operations below).  machfb clears the screen and the kernel output
simply continues with the the "wsdisplay0" line at the top of the screen
through to the hang.  The message buffer is not replayed.

OK, genfb does replay the message buffer.  Messages are the same as
the 5.0 dmesg posted previously.  The font change means I can't see
back before "pchb0 at pci0 dev 0 function 0".  genfb-specific output:

[...]
genfb0 at pci0 dev 18 function 0: ATI Technologies 3D Rage Pro
genfb0: framebuffer at 0x81000000, size 1024x768, depth 8, stride 1024
wsdisplay0 at genfb0 kbdbux 1: console (default, vt100 emulation)
drm at genfb0 not configured
[...]
[hung]

In another message you wrote:

> I see neither USB nor IDE devices attaching. How long did it sit there?
> If USB is the problem there might be error messages after a few minutes
> but I'd guess there's something wrong with the IDE driver :/

I've let it sit there for a few hours with no further progress.  Same
behavior (message-wise) on both 5.0_STABLE and -current (5.99.24 as of
03:00 or so CST 12 March 2010)

> So, it looks like your iMac wakes up in something else than 8 bit colour 
> depth ( unlike all my machines ) and machfb always seems to assume 8 bit. 
> That would at least explain the garbage you're seeing.
> In order to confirm or contradict please do the following:
> - - cold start the iMac and check what's in the graphics chip's depth 
> property ( do 'dev screen', then '.properties' )

Since I have "auto-boot? false", it comes up to the OFW prompt by
default.  'dev screen' followed by '.properties' yields:

[...]
depth                   00000008
[...]

So it looks like the 8-bit depth property is there.

> - - boot OSX, drop back to OF, check the depth property again

So, from here, I use 'mac-boot' to boot MacOS X, then just click the
"Restart" button on the login window.  The machine resets and I'm back
in OFW.

[...]
depth                   00000008
[...]

So, no change.  Maybe machfb is missing some initialization step that
MacOS X's driver does and which persists as long as the power is on?
Might be a quirk of the 3D Rage Pro?

> I might have to add code to either let machfb deal with colour depths other 
> than 8 or make it switch to 8 if necessary.

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