View Single Post
Old 01-05-07, 05:14 PM   #1
mdjr
Registered User
 
Join Date: Jan 2007
Posts: 4
Question Color problem (NV 420 Go)

Hello.

I do not know if this problem belongs here or to the hardware page.

I use Solaris on a laptop computer with an "420 Go" graphics card. The Solaris driver does not support this card however the "vesa driver" can use 1024x768x16 Mio. colors.

However I use a special background image. This image looks like only 64K colors and not 16M colors are used. For a foto 64K colors are enough but on the background image you see steps in the "fading colors".

By writing some test bytes directly to the screen memory (Address 0xA0000) I found out that the graphics card is really running in 16 Mio colors mode with four bytes per pixel (GG BB RR 00) but that the graphics card does not correctly display the colors of the image that are correct in the video memory.

Using Windows and Linux (original NV driver) the image is displayed correctly.

I do not know if it is that simple but if "only" some registers in the card had to be set (written to using the "out" instruction) I could write a device driver that simply changes the registers' values.
The NV driver seems to replace the card's firmware. This is too complicated for me!!

Anyone who has more information?

Martin

--- EDIT ---
To get more information about this problem I used the following test image:
The image has a size of 256xN while pixel (X,Y) has the color value (R,G,B)=(X/2, 127-X/2, 0).
The color should "fade" from red to green in 128 steps. However it fades in 32 steps.
This means to me that only 18 of the 24 color bits are used by the card's hardware.
I booted the old MS-DOS and found out that when using the on-board video BIOS of the card there is the same color problem so I think the actual problem is that the on-board video BIOS does not do all the settings the nVidea driver does.

Last edited by mdjr; 01-07-07 at 02:33 AM.
mdjr is offline   Reply With Quote