Re: apm-bios and rtc

C. Scott Ananian (
Mon, 2 Mar 1998 17:56:42 -0500 (EST)

On Sun, 1 Mar 1998 "Garst R. Reese" <> wrote:

> I finally got apm_bios to blank my screen with no error msgs.
> In apm_bios.c, I set APM_SET_DISPLAY_POWER_STATE "b" to 0x0100 instead
> of 0x01ff.
> After many printk's I disabled rtc support in the kernel. That did the
> trick.

Could you confirm that 0x01FF *doesn't* work, even if rtc support is
turned off?
[i'm currently compiling a 'minimal' kernel to see if I can track down
some other apm anomalies]

> APM bios V1.0 (Driver version 1.3), linux 2.1.88, PCMCIA-cs v3.0.0
> MidWestMicro Elite Soundbook DX2/66

What BIOS is your laptop using (should be displayed in a message at boot;
my laptop reads 'Phoenix BIOS 4.05')?

> I also noticed in console.c that apm screen blanking is called if
> CONFIG_APM is set. Shouldn't this be ifdef CONFIG_APM_DISPLAY_BLANK ?

No, see drivers/char/apm_bios.c, function apm_display_blank.
All APM-related options are restricted to the apm_bios.c file so that the
#defines at the top of apm_bios.c work as you would expect them to.

@ @
C. Scott Ananian: / Declare the Truth boldly and
Laboratory for Computer Science/Crypto / without hindrance.
Massachusetts Institute of Technology /META-PARRESIAS AKOLUTOS:Acts 28:31
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