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Re: unsupported display? (dual scan on PowerBook 2400 & G3)



Michael Blakeley wrote:

In article <3B379E50.50504@russisk.no>, lhs@russisk.no (leif) wrote:

Are you sure you have/had the dual scan version of the 2400c? There were one version at 180mhz and another at 240 mhz. Probably the 180mhz is with dual scan.


Let's make sure that we're using 'dual-scan' to mean the same thing. My 2400/180c has a 'dual-scan' video mode, which means that it displays the same video on the LCD and on an external monitor.


My PB has the same feature, but no, this is not what I was referring to. Here is a description of dual-scan displays:
<http://til.info.apple.com/techinfo.nsf/artnum/n24295>
and I quote: "The dual-scan color passive-matrix display actually consists of two displays butted up against each other." I.E. it is a special kind of LCD technology. It was (is) a cheap color LCD display compared to the actice matrix displays which now (I think) prevails.


Is that what you mean by 'dual-scan'? I'm only asking because you seem to be laying a lot of stress on that feature, but AFAIK all 2400's (180 and 240) had dual-scan video.


According to the accurate terminology one one of the 2400's did have dual-scan display. (From what I have seen an external display is called a 'monitor', while the monitor that comes with a lap-top is called a 'display'.)


If that's not what you mean by 'dual-scan,' then please elaborate.


Dual-scan is the name of a special type of LCD-display. Most of the linux-safe Powerbooks have Active Matrix displays. But my PB has a 'dual scan passive matrix' display. I cannot explain it technically other than with the words from TIL which I quoted above.


I haven't ever used it in Linux with dual-scan enabled,


You should call this 'duplication of the screen image on an external monitor' or something.

but I've run Linux with both displays (LCD and external VGA) at different times.


My attemt to install showed that there were no problems having screen image duplication. The fact that the installer stopped when coming to X-install (I'm now talking about my YDL2.0-attemt), must have been because the intaller was in doubt about which monitor/display to take into account or for other reasons having become comfused by the duplicated view. Or - most likely - for having trouble with my dual scan passive matrix display.

Generally Linux will start up using whatever mode MacOS left the display in. In theory you could write a command-line tool to switch between external, internal, and mirrored/dual-scan modes (like Ben's m3mirror tool for the new ATI M3 chips), but AFAIK no one's written such a tool for the 2400's CT display.


My expectations are a little more basic... I simply want to have linux on my pb. This is possible it seems. But it is not possible to use the dual scan display as for now... The only distributions I haven't checked out are SUSE and Mandrake.

--

 Leif Halvard

Oslo





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