Re: Please explain this: (suspend/resume w/ RH 9 on Dell Latitude C840)

From: Jim Bianchi (jimbo_at_sonic.net)
Date: 11/29/03 

Date: Sat, 29 Nov 2003 22:47:03 GMT

On Wed, 12 Nov 2003 15:55:53 GMT, Al Schapira wrote:
>I am running Red Hat 9 on a Dell Latitude C840 laptop with a 1400x1050
>display, NVidia GeForce 4 (generic) built-in card and 32 MB video
>memory. Everything including X, Gnome, etc, works very well, but there
>are a couple of things I just don't understand having to do with various
>ways of suspending and resuming. (I have NOT installed proprietary
>Nvidia drivers because I felt no need to since the included drivers work
>fine. Everything is right out of the Red Hat box with kernel 2.4.20-8.
>
        Hi, Al. I've a Dell Latitude C600 laptop (bo't it on eBay, and
upgraded to 512meg RAM, CD R/W - DVD drive, etc) that runs RH8. When first I
put RH8 on it, I wondered what this 'suspend' stuff was alla bout. I never
tried using fn+esc to suspend it (maybe I should've), I just closed the lid,
which, according to what (little) I understood, did the suspend thing, and
s'posedly would restore everything when the lid was opened again. Well, it
didn't exactly work out that way. (Yes, I did select the laptop install when
initially installing the system). As I recall (I only did this about twice,
and this was quite a few months ago), everything would be messed up, and
would require a cold boot to get things working again.

        What I did was to go into the BIOS setup, and change the 'suspend'
option such that it was off. Now when I close the lid, nothing changes, the
unit just keeps on doing what it was while the lid was open. In order to
shutdown the system, I must positively select 'shutdown' from the wm popup
(or issue a halt (or reboot) cmd from a terminal).

        Of course, I don't use the laptop at all often, and since I don't
work (retired) it's not required for much of anything. I bought it and did
the upgrades (WiFi and 56k modem PMCIA cards, mem upgrade, CD R/W - DVD
drive, and like that) mostly because I could afford it.

>How much of what happens is done by the BIOS, and how much by the
>kernel?

        Well, in my case, the laptop was originally intended for use with a
(ugh) Windoze op sys (as opposed to, say, Linux), so I suspect this is done
mostly by the BIOS -- but the Windoze op sys is obviously able to deal with
it. This question is sorta chickn & egg..

>Can someone explain just what is happening in each case?

        Again, my knowledge about this is mostly guesswork, but from what I
understand, when you push fn+esc (or close the lid), this triggers a signal
from the BIOS that tells the o/s to write its current state in a special
area on the hd and (temporarily) turn itself off. On my system, when the lid
is next opened, this will 'wake up' the BIOS, which in turn will tell the
o/s to read that special area on the hd, from which it will get what it
needs to 'rebuild' things such that anything running prior to this will be
running again. Again though, I suspect the o/s must be optimized for this
kind of thing -- it should 'know' about those signals from the BIOS, and
what to do when it gets them, it should know where that spl area is on the
hd, and to look there to get the proper config, etc.
        
>What control, if any, do users have over this?

        I never bothered to look into it, as it occured to me this was just
another 'zample of Windoze foolishness, so as I say, I just turned it off.

        On page 6 of 7 in my BIOS setup thingy, there are several options
dealing with suspend mode. I just set them all to 'disabled.' The really
important one (for me) was "Display Close:" which I set to 'active.' The
help file displayed w/that option reads: "Determines whether the system
remains active or suspends when the lid is closed. Set to ACTIVE to keep the
computer on *with the display off* when the lid is closed. Set to SUSPEND to
have the system suspend when the lid is closed."

        There are several other options, such as 'ring-event resume,' 'alarm
resume,' and 'wake-up on LAN' olive witch're self explanatory. I disabled
all of them too.

        I got out my laptop to get the above BIOS info, and just for the
hallibut, tried fn+esc. Yup. That still suspended the system. Closing and
opening the lid restored it. Only sometimes the desktop still gets corrupted
badly. I'll prob not make much use out of this 'feature,' even though it
appears to function (most of the time) with linux. 

-- 
jimbo@sonic.net 
"There are only 10 kinds of people in the world;
those who understand binary, and those who don't."

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