Re: Linux on Capio II (Geode) ?

From: Edward Lee epl (me_at_linnix.com)
Date: 05/26/04 

Date: 26 May 2004 10:27:20 -0700

larwe@larwe.com (Lewin A.R.W. Edwards) wrote in message news:<608b6569.0405251813.6a8d5bc0@posting.google.com>...
> > > {time period} a nonmaskable SMM interrupt occurs. The Geode hardware
> > > doesn't support text modes natively. In text modes, the SMM ISR checks
> > > to see if the color or character memory has changed, and if so it
> >
> > We are using a Geode GX1 based Compaq Internet Appliance 2. We have
> > not experienced any of the problem you mentioned. The only strange
>
> Are you using text modes? The discussion we're having here relates to
> use of modes which, ordinarily, would be supported by character
> generator hardware (which the CS5530/GX1 combo lacks). Font/color
> rendering, blink text and cursor are all emulated in unpreemptible
> firmware. You'll note that there are many Geode BIOSes out there that
> show significant problems with text-mode scrolling in Linux, BTW.
>

Yes, we are using text mode for Dos and Linux, piror to run X. The
scrolling is slow, but not unusually slow.

> There are other functions in Geode which also go through this baroque
> arrangement of HW/SW codependency, but text mode display rendering is
> one of the biggies. Geode is not a good choice for realtime
> applications unless you can get great vendor support for customized
> BIOSes (and not always even then).
>
> > thing is that I can only run at 1024x768 and my friend can only run at
> > 800x600. Any other video mode would get the monitor out of sync. I
> > am using Xfree 3.3.6 and my friend is using Xfree 4.2. Any idea why?
>
> The changes between these two versions are pretty radical, and in the
> case of 3.x servers, there are at /least/ three different forks of the
> source tree; two closed-source XF86_SVGA servers (one from NS, one
> from a third party I have yet to identify), and one official
> open-source version from xfree86.org. I don't know that there is any
> good source of documentation on all of this besides the XFree86
> source. Unfortunately the "official" NS sources are only available
> with an NDA (? I'm not sure how this is reconcilable with GPL).

I am using the open source XFree 3.3.6. I am not surprised that my
friend's system work on 800x600 only, since the original box (for msn)
was designed to run at 800x600. What's surprising is that I can only
run at 1024x768, with an external Multi-Sync monitor.

I have tried modeline timings from my own (worked on many other
systems), the example on your site and another one from the web. None
of them can get the display to work in 800x600.

It appears that the system has a firmware limitation coded somewhere
to a fixed resolution.

>
> Anyway, these versions all differ substantially in how they calculate
> and validate clock settings. The symptom you describe is, I'd say, par
> for the course (it can be instructive to scope the sync lines and see
> what's being set up, BTW!). If you are very careful to specify exact
> video mode setup in the ModeLine, you can *usually* get a particular
> mode working [except scandoubled modes - a patch is required for 4.x -
> see my webpage] but really the only way to ensure identicical behavior
> between systems is to use the _exact_ same binaries. An alternative
> option is to use the fbdev server running over kernel framebuffer
> console.
>
> One problem with 4.x servers is that all the "built-in" implicit
> modelines need to be overridden. It can be very hard to work out
> exactly where the server is picking up its config information
> sometimes, and/or hard to work out why it is rejecting user-supplied
> modelines.