Comment 15 for bug 112132

I have almost exactly the same problem. Or maybe not.

It's an HP PCm7170n with an Asus P5LP-LE (Lakeport) motherboard with a Pentium D 3.00Ghz (Smithfield)
Specs are here:
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00379616&lc=en&cc=ca&dlc=en&product=483897

I did an install from ubuntu-7.04-alternate-i386.iso. No problem on the install. The initial reboot after install was no problem (likely dumb luck). The reboot after the first update, including an update from 2.6.20-15-gereric to 2.6.20-16-generic, it failed to load. Going into grub and selecting any kernel option from the menu got the same result.

The main difference in what I get is that I am able to get it to boot once in a while. If I see the status bar does not move in 3 seconds I do Ctrl-Alt-Del. I have to do that between 2 and 7 times before it comes up. Once up, I have no trouble from that point on. If I reboot (with/without a power off), I have to do Ctrl-Alt-Del many times and it's up again.

When it fails, this is part of what I see in the recovery boot screen:

[ 41.032130] ata3.00: qc timeout (cmd 0x27)
[ 41.032179] ata3.00: ata_hpa_resize 1: sectors = 398297088, hpa_sectors = 0
[ 41.032231] ata3.00: ATA-7: Maxtor 6V200E0, VA111630, max UDMA/133
[ 41.032274] ata3.00: 398297088 sectors, multi 16: LBA48 NCQ (depth 0/32)
[ 41.032321] ata3.00: failed to set xfermode (err_mask=0x40)
[ 41.032363] ata3: failed to recoversome devices, retrying in 5 secs
[ 76.176415] ata3.00: qc timeout (cmd 0x27)
[ 76.176464] ata3.00: ata_hpa_resize 1: sectors = 398297088, hpa_sectors = 0
[ 76.176522] ata3.00: failed to set xfermode (err_mask=0x40)
[ 76.176564] ata3.00: limiting speed to UDMA/133:PIO3
[ 76.176605] ata3.00: failed to recoversome devices, retrying in 5 secs
[ 111.324358] ata3.00: qc timeout (cmd 0x27)
[ 111.324407] ata3.00: ata_hpa_resize 1: sectors = 398297088, hpa_sectors = 0
[ 111.324465] ata3.00: failed to set xfermode (err_mask=0x40)
[ 111.324507] disabled

Done.
     Check root = bootarg cat /proc/cmdline
     or missing modules, devices: cat /proc/modules ls /dev
ALERT!
     /dev/disk/by-uuid/f3892a94-011d-4c74-a6ee-94d35d1d210d does not exist
     Dropping to a shell!

The directory /dev/disk/by-uuid does not exist when it fails to boot, but does exist when it does boot.

I have not tried any of the workarounds mentioned above as I have been able to get it running with Ctrl-Alt-Del.

Happy to send any other info requested.