On Tue, Jun 19, 2007 at 02:29:20AM +0200, Stefan Reinauer wrote:
- Uwe Hermann uwe@hermann-uwe.de [070619 02:24]:
General question: is there some reason to configure the PAM-controlled areas to something other than "read/write" in any case? Do any modern OSes or payloads which we might want to support _need_ the PAM regions to be something other than read/write?
Yes. ADLO.
OK, so we'll have to take care about that.
Which settings does ADLO require/expect?
Here's a list of the PAM registers and which regions they enable (on 440BX):
PAM Reg Attribute Bits Memory Segment Comments Offset PAM0[3:0] Reserved 59h PAM0[7:4] R R WE RE 0F0000h 0FFFFFh BIOS Area 59h PAM1[3:0] R R WE RE 0C0000h 0C3FFFh ISA Add-on BIOS¹ 5Ah PAM1[7:4] R R WE RE 0C4000h 0C7FFFh ISA Add-on BIOS¹ 5Ah PAM2[3:0] R R WE RE 0C8000h 0CBFFFh ISA Add-on BIOS¹ 5Bh PAM2[7:4] R R WE RE 0CC000h 0CFFFFh ISA Add-on BIOS¹ 5Bh PAM3[3:0] R R WE RE 0D0000h 0D3FFFh ISA Add-on BIOS 5Ch PAM3[7:4] R R WE RE 0D4000h 0D7FFFh ISA Add-on BIOS 5Ch PAM4[3:0] R R WE RE 0D8000h 0DBFFFh ISA Add-on BIOS 5Dh PAM4[7:4] R R WE RE 0DC000h 0DFFFFh ISA Add-on BIOS 5Dh PAM5[3:0] R R WE RE 0E0000h 0E3FFFh BIOS Extension 5Eh PAM5[7:4] R R WE RE 0E4000h 0E7FFFh BIOS Extension 5Eh PAM6[3:0] R R WE RE 0E8000h 0EBFFFh BIOS Extension 5Fh PAM6[7:4] R R WE RE 0EC000h 0EFFFFh BIOS Extension 5Fh
Do we have or want a general LinuxBIOS-wide policy as to how to set the PAM registers? Or is this chipset-/mainboard-specific?
IMO we should make sure that ADLO can be used on _all_ boards. It's no problem to have a config option and a reasonable default, but there should definately be a possibility for the "end user" to easily use ADLO without having to touch the source code.
Uwe.