[prev in list] [next in list] [prev in thread] [next in thread] 

List:       linux-kernel
Subject:    Re: [PATCH] Guarantee APM power status change notifications
From:       Bill Davidsen <davidsen () tmr ! com>
Date:       2002-07-31 20:10:48
[Download RAW message or body]

On 31 Jul 2002, Ray Lee wrote:

> There are three cases. First, the BIOS doesn't send any notifications;
> this is fixed. Second, the BIOS sends notifications. In this case, the
> code notes that, and disables the workaround. Third, the BIOS sends
> notifications, but somehow we managed to notice the power change before
> the BIOS could tell us. This seems highly unlikely, but what the heck,
> it could theoretically happen. In that case, we disable the workaround,
> and drop the notification that the BIOS generated, as we already sent it
> onward up the call chain.

Actually there is one more case, where the BIOS unreliably tells you
something has changed. I have an old Toshiba which I bought with Windows
installed, and it always noticed pulling the plug and going line=>battery,
but only sometimes noticed battery=>line. Of course this might be an o/s
bug. Can't test that any more, the battery failed and the transition is
now line=>dead.

Anyway, if you are paranoid you could just ignore the "I knew that" cases
and leave the workaround in place, unless that would generate other
issues.

-- 
bill davidsen <davidsen@tmr.com>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
[prev in list] [next in list] [prev in thread] [next in thread]