RE: [OpenBIOS] success on l440gx+ ram

[David Christensen]

After rereading this I realized I forgot a few things.  Before you can
search for the VGA you'll need the traverse the PCI bus hierarchy and setup
the primary, secondary, and subordinate bus numbers in the PCI bridge
registers.  Next you'll need to scan through all of the PCI devices, looking
for the VGA controller.  Once you've programmed the I/O and memory
requirements for the PCI VGA then you'll need to check if there are any PCI
bridges that need to have an aperture opened up to allow access that memory
and I/O you just enabled.  Also, if the card has an IRQ you'll need to know
how the interrupt is routed to it and program the PCI IRQ in the PIIX4.
Also, don't forget to enable the I/O and memory addresses in the PCI command
register.

Hopefully a lot of this is already taken care of in OpenBIOS (especially the
PCI bus enumeration).

Dave

-----Original Message-----
From: [e-mail]
[mailto:[e-mail]]On Behalf Of
David Christensen
Sent: Tuesday, February 15, 2000 10:21 PM
To: [e-mail]
Subject: RE: [OpenBIOS] success on l440gx+ ram

Are you using an ISA VGA adapter or a PCI/AGP video adapter?  The ISA
adapter would be easier, setting up real mode and make a FAR CALL to the
OPROM at address 0x000C0003.  (Make sure your stack pointers are setup.)
PCI is a lot more complicated.  Probe the VGA BARs and assign the required
I/O and memory resources.  Probe the PCI expansion ROM BAR and enable it at
a convenient memory location.  Next you'll need to access the PAM registers
in the 440GX and setup a read/write memory region starting at 0x000C0000, at
least as long as the expansion OPROM.  Copy the OPROM down into the
read/write shadow memory.  Turn off the expansion ROM, setup for real mode,
then make a FAR CALL to the OPROM just like the ISA VGA case.  When the VGA
OPROM returns check the size of the OPROM and set the PAM registers in the
440GX to read-only mode.  Now you should have video.  Easy as pie.

Dave

-----Original Message-----
From: [e-mail]
[mailto:[e-mail]]On Behalf Of
Ronald G. Minnich
Sent: Tuesday, February 15, 2000 6:18 PM
To: [e-mail]
Subject: [OpenBIOS] success on l440gx+ ram

I forgot to put a 0x17 in reg 0x76 after the mode set command. Sheesh.

dram is now working fine. I am actually in protected mode in the 32-bit
openbios startup, getting ready to gunzip linux and jump to it.

Now the trick is to figure out why I have no display :-)

All I want for now is a vga-compatible thing, very limited in scope. So I
want the absolute minimum hardware only. Any hints would be welcome.

ron

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