Subject: Re: port-i386/5786: APM: unknown error code
To: Kimmo Suominen <>
From: Rene Hexel <>
List: netbsd-bugs
Date: 07/25/1998 06:37:12
Kimmo Suominen wrote:

> >  Have you tried "options APM_NO_IDLE" in your kernel config?
> I guess that would get rid of the errors, but otherwise I'm not sure
> if it would be the right thing to do.  I'd like to understand why apm
> thinks this is an error -- must be a bug, since the error code matches
> the BUSY and IDLE commands of apm.

  AFAIK the IDLE and BUSY calls usually cause CPU clock frequency to be
reduced in order to lower heat and energy consumption.  Since this makes
more sense on notebooks than on desktop computers it seems that some
motherbord manufacturers chose not to implement this feature on their
boards.  I had the same problem with a Gigabyte 586DX motherboard, for
instance ...

  The error message ("unknown error code") seems to stem from a parsing
problem.  It looks like error codes 0x5306 and 0x5305 are combinations
of 0x53 ("Command not supported") and 0x06 ("CPU busy") or 0x05 ("CPU
idle"), respectively.  As I'm not an APM expert I cannot say whether
this really is a (cosmetic) parsing problem on NetBSD's side or whether
these are non-standard error codes issued by the motherboard(s).  (Since
this happens on more than one motherboard I reckon that the first
assumtion is the correct one).