i915 and some more research

[Alan Hourihane]

On Mon, Apr 25, 2005 at 10:18:55PM +0200, Kim Schulz wrote:
> Hi again. 
> I have recently been playing around with the 855resolution tool on my
> laptop with i915 chipset. 
> I noticed that this tool recognizes more resolutions reported by the
> bios that xorg does. 
> 
> This is what 855resolution gives me:
> 
> Chipset: 915GM
> VBIOS type: 2
> VBIOS Version: 3412
> 
> Mode 30 : 640x480, 8 bits/pixel
> Mode 32 : 800x600, 8 bits/pixel
> Mode 34 : 1024x768, 8 bits/pixel
> Mode 38 : 1280x1024, 8 bits/pixel
> Mode 3a : 1600x1200, 8 bits/pixel
> Mode 3c : 1920x1440, 8 bits/pixel
> Mode 41 : 640x480, 16 bits/pixel
> Mode 43 : 800x600, 16 bits/pixel
> Mode 45 : 1024x768, 16 bits/pixel
> Mode 49 : 1280x1024, 16 bits/pixel
> Mode 4b : 1600x1200, 16 bits/pixel
> Mode 4d : 1920x1440, 16 bits/pixel
> Mode 50 : 640x480, 32 bits/pixel
> Mode 52 : 800x600, 32 bits/pixel
> Mode 54 : 1024x768, 32 bits/pixel
> Mode 58 : 1280x1024, 32 bits/pixel
> Mode 5a : 1600x1200, 32 bits/pixel
> Mode 5c : 1920x1440, 32 bits/pixel
> 
> 
> and this is what xorg gives me:
> www.cs.aau.dk/~kim/Xorg.0.log

This is because the tool goes poking in the BIOS, rather than actually
making a BIOS call for valid modes.

Now, the BIOS intelligently removes modes that are incapable of being
displayed on the LCD. So, in your case, 1920x1440 cannot be displayed
on your LCD and the BIOS removes the mode from it's pool. Same for
1600x1200 as your panel is only 1680x1050.

Alan.