ownerboot/doc/platform/kgpe/notes.md

kgpe: platform-specific notes

quirks

hang during boot if vga enabled

If the system hangs on startup before attempting to boot the ownerboot Linux kernel, and the last few messages you see on the console look like the following, try disabling the on-board VGA output (move jumper VGA_SW1 to the two pins closest to the pci slots):

...
PCI: 00:14.1 10 <- [0x0000003030 - 0x0000003037] size 0x00000008 gran 0x03 io
PCI: 00:14.1 14 <- [0x0000003048 - 0x000000304b] size 0x00000004 gran 0x02 io
PCI: 00:14.1 18 <- [0x0000003038 - 0x000000303f] size 0x00000008 gran 0x03 io
PCI: 00:14.1 1c <- [0x000000304c - 0x000000304f] size 0x00000004 gran 0x02 io
PCI: 00:14.1 20 <- [0x0000003010 - 0x000000301f] size 0x00000010 gran 0x04 io
PCI: 00:14.2 10 <- [0x00f0404000 - 0x00f0407fff] size 0x00004000 gran 0x0e mem64
PCI: 00:14.3 a0 <- [0x00f0410000 - 0x00f0410000] size 0x00000001 gran 0x00 mem

watchdogs

The KGPE-D16 has at least three separate hardware watchdogs!

• One in the SB700 southbridge, although it appears to be disabled (Linux's sp5100_tco reports that it cannot be enabled).

• One in the W83795 hardware monitor (thermal/fan control chip)

• One in the W83667HG-A SuperIO chip

I've found the third one to be most reliable. The Linux w83627hf_wdt kernel module for this watchdog works correctly, and I was able to write a coreboot patch (to be included with ownerboot) to start the watchdog extremely early in the boot process -- before DRAM initialization or PNP enumeration. This is extremely helpful with unattended servers, where a hang in the boot process requires manual power-cycling.