First I'd like to describe a problem I've encountered:
I have a virgin motherboard that has never been powered up before. i.e. this board was not manufactured elsewhere and a 'standard' BIOS has never been used on it.
When booting this board I discovered an interesting problem: the boot would hang when the "hwclock" tool was invoked by /etc/rcS.d/<some script that reads the rtc>.
The underlying problem is that this common linux utility is reading the RTC via the standard IO ports 70-71. Within this RTC window all of the dallas semiconductor RTC clones use a few bits in register 0x0a to enable the clock when power is down. The default values of these bits do not enable the clock - presumably to avoid draining the battery until the boards are first placed into production.
I've modified my version of linuxbios to ensure that these bits are set to enable the RTC updates. My question is, where is the best place to make this change?
1) In some non linuxbios component (i.e. some little app run at boot time)
2) In linuxbios, but restricted to my mainboard.
3) In linuxbios, but in 'common' code that applies to all intel boards.
I'm in favor of option 3, but I thought I'd ask first. I think this problem would apply to any board. The reason we haven't seen it before is that most folks are running linux bios on boards that once had a standard bios. The standard bios has already 'activated' the RTC updates.
What do you think?