Re: LCD Screens supported by linux

From: Floyd L. Davidson (floyd_at_barrow.com)
Date: 12/22/04 

Date: Wed, 22 Dec 2004 11:50:43 -0900

Michael Heiming <michael+USENET@www.heiming.de> wrote:
>> Note that I had to set the HorizSync range to 30-80 rather than
>> the 30-79 the manual specified. With it set to 30-79 the 75 Hz
>> refresh 1280x1024 mode, with it's 79.976 KHz rate, was not
>> selected. The significant point of the above is that all of the
>> modes I wanted used a 75 Hz vertical refresh rate, and hence I
>> could get them all by specifying just one rate rather than a
>> range, and therefore eliminate all of the modes that I did not
>> want.
>
>AFAIK refresh rate is more or less irrelevant on a LCD, as it
>doesn't refresh the screen at all, there's a range given in my
>XF86Config for my LCD, but it's always (xvidtune) at exactly
>60.02 Hz. On other systems with the same LCD, the monitor moaned
>about to high values, there was a pretty good CRT attached
>before, edited to 60 and it works as nice.

It doesn't have quite the same meaning for an LCD as it does for
a CRT, but yes it is relevant. Of the two different models of
LCD that I've used with an analog video card, each has a totally
different set of possible vertical refresh rates. On one model
I did in fact experiment with both 60Hz and 75Hz long enough to
determine that the 60Hz rate *definitely* bothered my eyes. I
found that interesting because I've never had a 60Hz rate on a
CRT particularly bother me (I've sat and looked at a 60Hz
refresh rate on a CRT without trouble while other people told me
they were unable to look at it for more than 15-20 seconds...).

The main significance is that a CRT (an inherently analog
device) can be changed in continuous increments, but a LCD (an
inherently digital device) can _only_ work at discrete
frequencies.

>[..]
>
>> Using an LCD monitor is not really much different than using a
>> CRT, as such. The difference is that an LCD *must* used the
>> modes it was intended to support, while a CRT can be warped into
>> modes that were not considered by the manufacturer.
>
>Yup, if one does lots of gaming probably with various video modes
>not the default of some LCD panel, a CRT should do a better job.
>
>Any other mode on my LCD, then 1280x1024 the panel size, doesn't
>look that great.

Mine seems fine at lower resolutions too. But certainly there
is *no* way to use higher resolution scan rates than the maximum
it is designed for. I commonly did exactly that with CRTs,
though of course the "benefit" is debatable because it might
well have been able to display an image, it certainly did not
have the bandwidth to actually provide definition to the
"resolution" that I was running it at.

The cheap Norwood Micro LCDs that I bought don't have the
ability to retain different configuration (size and position,
for example) for different modes though. Even the 10 year old
Viewsonic 17" CRT it replaced could do that...

>> Hence in my case the significant point is exactly as expected,
>> the real difference is 1) less real estate occupied on my computer
>> table, and 2) the mind boggling result of having two 19" screens
>> instead of two (less than) 17" screens.
>
>I'm thinking about getting a second 19" LCD, probably a cheaper
>one, which seem to be available for not even half the price of an
>Eizo. There's somewhere a 16MB voodoo3 PCI flying around, which
>might be enough to get Xinerama working.
>
>Still fear that the second display won't be used if it's
>mentionable worser then the first.;(

*Do it!* I'll just about guarantee you will like the results.
My layout puts all the static stuff (fvwm's button-bar, page
manager, xcalc, xmms, xsysinfo, and xload, plus a small xterm
logged into my firewall) all on the right window, while I
basically work in the left window 90% of the time. Everything
on the right screen is sticky (I used 15 virtual desktops), so
it is always there no matter where I'm at.

Once in awhile of course I want two editor windows open full
screen next to each other. Or I want gv to display something in
one window whilst I edit the TeX code. (And for some people the
time they do that would be 90% instead of my 10%.) 

-- 
Floyd L. Davidson           <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska)                         floyd@barrow.com