[coreboot] Problem with the RTC
Stefan Reinauer
stepan at coresystems.de
Sat Nov 15 12:50:44 CET 2008
On 15.11.2008, at 11:47, Chris Lingard <chris at stockwith.co.uk> wrote:
>
> coreboot-v2 has been giving the following error:
>
> PCI: 00:01.0 init
> set power on after power fail
> RTC Init
> Invalid CMOS LB checksum
> PNP: 002e.1 init
>
> I have put some debugging in rtc_checksum_valid of mc146818rtc.c to
> output the variables, and got
>
> PU model AMD Athlon(tm) 64 X2 Dual Core Processor 6000+
> Setting up local apic... apic_id: 0x01 done.
> CPU #1 Initialized
> All AP CPUs stopped
> PCI: 00:18.0 init
> PCI: 00:01.0 init
> set power on after power fail
> RTC Init
> Sum f31c
> Old Sum f31c
> Sum cfe1
> Old Sum 2225
> Invalid CMOS LB checksum
> PNP: 002e.1 init
>
> This persists on reboot, and on cold start. I have no idea why the
> second call to this procedure results in this, but think it is a
> timing problem.
The first sum is the 'normal of bios checksum' while the second is an
extended checksum.
You can correct it by changing a setting with nvramtool
Stefan
>
>
> This procedure is called twice from rtc_init, and I think that the
> second call is wrong; so I changed the second one:
>
> /* See if there is a LB CMOS checksum error */
> /* checksum_invalid = !rtc_checksum_valid(LB_CKS_RANGE_START,
> LB_CKS_RANGE_END,LB_CKS_LOC); */
> if(checksum_invalid)
> printk_debug("Invalid CMOS LB checksum\n");
> {
> /* Make certain we have a valid checksum */
> rtc_set_checksum(PC_CKS_RANGE_START,
> PC_CKS_RANGE_END,PC_CKS_LOC);
> }
>
> checksum_invalid is already set, so the second call to
> rtc_checksum_valid is commented out
>
> The check sum was being written back every time, right or wrong, so
> I have put rtc_set_checksum within the failure bit.
>
> Chris Lingard
>
>
>
>
>
>
>
> --
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