Re: External CRT works on 1024x768 but LCD not. Please Help!!!

Alan Hourihane wrote:

> On Sat, Feb 19, 2005 at 08:17:07PM -0300, Nqnsome wrote:
> > Hi Christian,
> >
> > Thanks for answering.
> >
> > Christian Zietz wrote:
> >
> > >I still suppose that your BIOS only recognizes the LCD as a 800x600 one,
> > >while the CRT is recognized correctly as being able to display 1024x768.
> > >The Windows XP driver doesn't care about the BIOS but bypasses it. X on
> > >the other hand needs the BIOS to set the resolution because the
> > >information on how to do that without the BIOS is not publicly available.
> > >
> > >CU Christian
> > >
> > >
> > Sorry, but what do you mean with "how to do that"? What kind of
> > information is (not!) in the BIOS that tells X how to change the
> > resolution? A function? A memory address? Something else?
>
> No. Christian is saying that the programming information is not publicly
> available so that the driver can bypass using the BIOS. Which is what
> the Windows drivers do.
>
> > I am asking this because, if I have more information about what is
> > possibly broken/missing in the BIOS, I can try to contact the
> > manufacturer and ask for a fix. Without specific information it is
> > difficult to get a useful answer from the manufacturer (COMPAL).
>
> Just tell COMPAL that the ModeAttributes field for bit 0 which is
> called 'Mode supported by hardware configuration' is not being set
> when asking the Video BIOS for available supported resolutions with
> the LFP (Local Flat Panel). The Video BIOS call is 0x4F01 with the
> mode set to 0x34 for 1024x768 at 8bpp, 0x45 for 1024x768 at 16bpp
> and 0x54 for 1024x768 at 32bpp.

Let me write you a small program to read the value. Then can be sure if plugging the external crt confuses the BIOS. You have a very valid point :) WHY IT WORKS ON WINDOWS. Can you boot DOS?

>
>
> Alan.
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