First post, by wbc
Hi all,
I have been used my Matrox Millennium for years in my P200MMX box (paired with S3 Trio3D/2X sometimes for lowres VESA stuff) and i have noticed jittering issues in 800x600 32bpp in DOS (lower bit depths works fine). With UniVBE 6.53 (5.3 doesn't work correctly), things are becoming more interesting! 😀
// here goes a bit of technical thoughts, which may be incorrect (or not 😀)
As SDD adds lowres support, and Millennium is a pretty tricky in terms of low-level display interacting (i.e. it features an limited amount of available screen pitches (or bytes per scanline), probably multiples of 128 (VESA modeinfo report without or with UniVBE), confusing a lot of programs), no doubts you will never achieve full 100% compatibility. So with SDD 320x200 32bpp jitters with any refresh rate, with 320x240 it occurs when vertical rate drops below 65 Hz, same for 800x600.
All of there somes have non-exact pitches (not (width*bytes_per_pixel) == 1280 but rather 2048 or something like that) so, as I suspect, jitter is caused by memory to RAMDAC interface or timing issues (in VESA and hires modes in general pixel data goes from memory directly to RAMDAC, bypassing graphics controller, which is only generating sync timings and memory addresses).
Besides that, Matrox is of course barely usable for hardcore VGA/VESA stuff, being more suitable for hires and accelerated 2D graphics under Windows and so on 😉 so no worries anyway from me
Any other suggestions?
--wbcbz7