>I haven't implemented this yet within linuxbios V1 but I will try it out and
>post again.
It's pretty irritating. When I turn 00.0 byte $88 bit 1 to 1, the MB
locks up. Turning that bit on enables the graphics aperture. I'm going to
just do it in a userspace program, which works fine.
I can put this in V1 src/mainboard/via/epia-m/earlysetup.inc at the top:
// set AGP aperture size to 128M
movl $CONFIG_ADDR(0, 0x00, 0x84), %eax
movb $0x80, %dl
PCI_WRITE_CONFIG_BYTE
// enable AGP
movl $CONFIG_ADDR(0, 0x00, 0xa9), %eax
movb $0x01, %dl
PCI_WRITE_CONFIG_BYTE
// Move AGP to safe place before enabling
movl $CONFIG_ADDR(0, 0x00, 0x10), %eax
movl $0xe0000000,%edx
PCI_WRITE_CONFIG_DWORD
However if I follow this with
movl $CONFIG_ADDR(0, 0x00, 0x88), %eax
movb $2,%dl
PCI_WRITE_CONFIG_BYTE
Then it locks up. I had thought it might be because the GART is supposed
to be in system memory, so if I try and turn it on before DRAM is ready, the
AGP system might try to read a page of the GART into its cache, and this
results in a fault since the memory isn't there. So I tried doing the last
turn on bit later after DRAM is initialized, but that didn't help.
-Dave