[LinuxBIOS] CMOS options questions

Steven J. Magnani steve at digidescorp.com
Thu Aug 25 19:05:00 CEST 2005


I am trying to finish up support for Intel's XE7501DEVKIT (E7501 Xeon
reference board) and have run into a snag getting CMOS options to work.

It looks like the factory BIOS uses pretty much the entire normal
128-byte region of the CMOS. So to support LB use of CMOS I will have to
use the upper 128 bytes.

Another option is to run this board without LB use of CMOS. But the
factory BIOS on this board does not like the changes LB makes to the
CMOS while booting. If I boot LB, then re-flash the factory BIOS and
boot it, the factory BIOS complains that the CMOS checksum is bad.

The questions:
* Is there any reason not to change hard-coded CMOS_IMAGE_SIZE constants

  from 128 to 256?

* Is there any reason not to change hard-coded accesses to RTC_BOOT_BYTE

  to equivalent read_option calls (accounting for the fact that the 
  fallback image, in which USE_OPTION_TABLE=0, may also need to be able 
  to read the 'boot byte' of the CMOS)?

* Is there any reason not to disable writing to CMOS (except for control

  registers) when HAVE_OPTION_TABLE = 0?

 Steven J. Magnani               "I claim this network for MARS!
 www.digidescorp.com              Earthling, return my space modulator!"
 #include <standard.disclaimer>

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