head -r356187 from TARGET_ARCH=powerpc vs. booting 32-bit on PowerMac G5's (64-bit hardware): fails in my context

[Mark Millard]

Historically 32-bit powerpc systems were my
"universal builds" in that they booted all the
PowerMac variants that I had access to (that
could boot FreeBSD at all).

But it has been a long time since I've dealt with
32-bit updates so the following report need not be
new behavior.

Also, I have patches for FreeBSD tied to handling
various PowerMac related oddities, so this report
is not about a pure official-FreeBSD build. (Those
have known problems of their own.)

I've access to 2 types of PowerMac G5's:

One with 2 sockets, 1 core/socket, 8 GiBytes RAM
Two with 2 sockets, 2 cores/socket, 16 GiB/12 GiB

Neither type makes it to a boot prompt. The
detailed behavior varies some between the
two types.

By the way, the G4 PowerMac example, used as a
contrasting 32-bit hardware context, has 2
sockets, 1 core each, 2 GiBytes RAM. This context
works.



For G5's with 2 sockets, 2 cores each:

Reaches "Root mount waiting for: CAM". Prior
to this things seem fine.

But it is stuck there, repeating the notice
and periodically reporting IO errors that
have run out of re-tries for the SATA SSD
(for the same SSD it just used to get this
far: no other media present).

It is the same SSD I boot in the G4 example
just fine. (I've historically moved media
around between compatible machines instead
of having separate media set up for each.)


For G5 with 2 sockets, 1 core each:

Reaches "Root mount waiting for: CAM". Prior
to this things seem fine. As expected the
messages do repeat a few times.

It does manage to output its equivalent of what
on the G4 looks like:

ada0 at ata2 bus 0 scbus2 target 0 lun 0
ada0: <OWC Mercury Electra 3G SSD 541ABBF0> ATA8-ACS SATA 2.x device
ada0: Serial Number <REPLACED>
ada0: 100.000MB/s transfers (UDMA5, PIO 512bytes)
ada0: 114473MB (234441648 512 byte sectors)
cd0 at ata1 bus 0 scbus1 target 0 lun 0
cd0: <PIONEER DVD-RW  DVR-105 A506> Removable CD-ROM SCSI device
cd0: Serial Number <REPLACED>
cd0: 16.700MB/s transfers (WDMA2, ATAPI 12bytes, PIO 65534bytes)
cd0: Attempt to query device size failed: NOT READY, Medium not present

(I decided to not take a picture for the G5 and
retype it all from the image.)

So it indicates doing some I/O with the SSD that
the other G5 type failed to do.

But it then complains about not being able
to handle /dev/ and ends up at the db> prompt.

It is, again, the same SSD I boot in the G4
example just fine. (I've historically moved
media around between compatible machines
instead of having separate media set up for
each.)


Note: I've not yet dealt with switching powerpc64
to an ELFv2-vintage FreeBSD.

===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)