Date: Wed, 05 Aug 1998 08:02:33 +0100 From: Brian Somers <brian@Awfulhak.org> To: Mike Smith <mike@smith.net.au> Cc: Brian Somers <brian@Awfulhak.org>, Randy Philipp <cphilipp@pop500.gsfc.nasa.gov>, Doug White <dwhite@resnet.uoregon.edu>, Greg Lehey <grog@lemis.com>, freebsd-mobile@FreeBSD.ORG, "Jeroen van den Boom" <jeroen@ctxnl.com> Subject: Re: Neomagic chipset - is it a hardware problem ? Message-ID: <199808050702.IAA12582@awfulhak.org> In-Reply-To: Your message of "Tue, 04 Aug 1998 07:24:15 PDT." <199808041424.HAA00456@antipodes.cdrom.com>
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[Jeroen van den Boom from CTX cc'd - this may interest you!]
[Greg cc'd - there's a question/request near the end... :-)]
It looks like you're at least partially correct Mike. I've done some
more tests with heating up, cooling down, restarting X, restarting
FreeBSD, suspend & resume and LCD off & on....
It seems that the screen corruption is due to a combination of the X
server initialisation (*not* doing something it should) and the heat
of the machine. If I start X and let the machine heat up, or start
X when the machine is already hot, I get the flickering.
Once it's flickering, the display can be made crystal clear again by
either suspending 'till the machine cools down (as I said before) or
by simply switching the LCD off and on (there's a small switch for
detecting when the lid is down that switches the LCD off by default
and can be configured to make the laptop ``sleep''). If I ``sleep
'till cool'', the problem re-occurs as the machine heats up again.
I can only guess that the sleep/resume is being caught by the power
management stuff and X is re-initialising (wrongly) the display
whereas the LCD off/on event is completely transparent and the laptop
firmware knows how to make the screen work when hot..... once this
`tweak' has happened, the display is fine forever more - up until it
goes into text mode and back into graphics mode (ala X server).
This is *very* peculiar, but I think it's now looking more like a
software thing. I'll continue to test things.... I'm now running
KDE 1.0 (window manager) and am using a screensaver - maybe this is
relevant. I *do* wish NeoMagic would just publish the damn specs :-(
The other ``weird'' thing is that nobody else seems to have reported
this problem, although I guess there aren't that many that have gone
to the trouble of manually merging the initialisation code, and even
fewer (if any) that have a CTX Cybernote. Greg, as you've got a
similar setup (although I doubt your machine is a CTX Cybernote), can
you try doing a ``make world'' and see if you get similar behaviour,
making sure that you *haven't* let the laptops LCD initialise itself
(X should be the last thing to have set up the display from text
mode) ? It would be much appreciated.
Thanks everyone for your help.
> > I've found out more about this flickering problem.... it only occurs
> > when the laptop is physically warm - the warmer, the more flickering.
> > If the machine sleeps for ~15 minutes, it'll wake up with a perfect
> > picture and that picture will start to deteriorate with the building
> > heat. If I switch the display off for 15 minutes it makes no
> > difference.
> >
> > This is all under load. If the machine is idle it lasts a lot
> > longer (the fan is more effective I guess....)
> >
> > Has anyone else seen this problem ? I'm pretty much convinced that
> > it's a hardware problem now, so I'll probably return the machine
> > (second time) nearer the end of the week.
>
> I've seen similar symptoms on a Toshiba using the C&T 65555. The part
> would misbehave so badly that the X server would crash.
>
> Windows worked OK on it though; my hypothesis was just that the X
> driver wasn't doing whatever power management stuff the Windows driver
> was, and so the chip was overheating. I could be way off on that
> though; I know nothing about the C&T architecture.
>
> --
> \\ Sometimes you're ahead, \\ Mike Smith
> \\ sometimes you're behind. \\ mike@smith.net.au
> \\ The race is long, and in the \\ msmith@freebsd.org
> \\ end it's only with yourself. \\ msmith@cdrom.com
--
Brian <brian@Awfulhak.org>, <brian@FreeBSD.org>, <brian@OpenBSD.org>
<http://www.Awfulhak.org>;
Don't _EVER_ lose your sense of humour....
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