Re: LCD screens work how?
On Fri, Sep 15, 2000 at 10:12:55AM -0700, Sean 'Shaleh' Perry wrote:
> A laptop's LCD screen is only good for one resolution. I throw a wide
> range of numbers at it and it picks the only one that works.
Both laptops I've worked with could handle different resolutions. The
older, Pentium 120 laptop, with C&T display card, has a 800x600 panel,
and I think does "integer scaling" (don't know what the official name
for it is.) Thus I think it used 640x600 pixels if you use mode 320x200.
I remember using it at 800x600, 640x480 (which didn't fill the panel,
of course), and 320x200 - I still want to go back at it and throw more
interesting modes at it... I cannot remember if I've done any mode other
than 800x600 under linux.
The laptop I work on at this moment, does proper scaling, with
smoothing, of many modes. (My text mode is "anti aliased"... <g>) I have
thrown at it: 1024x768, 800x600, 640x480, 640x400, 512x384, 480x300,
400x300, 320x240, 320x200, as well as 352x240... all of them were scaled
up to 1024x768, by hardware, with smoothing... brilliant. Note, however,
that this only works with the XF86_SVGA server. (And the "normal" modes
under M$Windows also works like this.) Running the Mach64 server on this
display at anything other than 1024x768 "melts" it, and the only
solution is hardware power-off... keyboard doesn't work either. My
XF86Config thus has only 1024x768 specified for "accelerated" servers. I
have given up on multiple modes and video mode switching with Mach64, so
I use the SVGA server when I need it. Oh, I haven't mentioned in this
mail yet: it is an ATI Rage Mobility display card.
This is why the fixed dot-clock makes sense: the display card is always
outputting 1024x768 - which is also why the hsync and vsync are pretty
meaningless. (As long as I enter any "valid" modeline, the card will
work at that resolution, with a dotclock of 65.15, and xvidtune will
report a refresh rate based on the resolution and that dotclock. The
modifications that can be made to the mode by xvidtune, have no effect
whatsoever. All I must do now, is figure out what is the simplest way
of making a modeline "valid" - i.e. not rejected by the X server, then I
can probably try any arbitrary resolution. I still want to try 4x3... ;)
I have now realised that the old Pentium120 will then possibly NOT have
a fixed dotclock, it can likely depend on the scaled resolution, thus
for 320x200 it will have a dotclock that is necessary to output
640x600(?) I will only be able to test this in two and a half weeks'
time, unless I can squeeze it in on Thursday (maybe). But I can try a
twisted mode on this laptop...
Hugo van der Merwe
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