Re: difference in maximum color depth in Debian vs Mac OS?
+----[ Brad Boyer <firstname.lastname@example.org> (31.Jan.2005 18:43):
| On Mon, Jan 31, 2005 at 03:04:35PM +0100, Hans Ekbrand wrote:
| > On Sat, Jan 29, 2005 at 02:31:40AM -0300, Fernan Aguero wrote:
| > > The VRAM of this Macintosh is 1MB (expandable to 4MB I
| > > believe). However what I fail to understand is why the Mac
| > > OS is able to get a higher color depth than debian/linux on
| > > the same hardware.
| If you look at the code for platinumfb, it believes that 1M isn't enough
| to do 832x624 in 16 bit color. There is a formula coded in to calculate
| how much VRAM any particular mode takes. It's something like this:
| vres*(hres*bpp + 32) + 4096
| Run the numbers, and it adds up to more than 1M. I have no idea where the
| constants are from, but the 32 appears to be the difference between the
| hres and the line length in the framebuffer. I don't know enough about the
| driver to figure out anything more. Perhaps some of the people who worked
| on the code are still around to answer these questions.
| Brad Boyer
Well spotted. I also don't know enough about this issue. I just
wanted to know if I was the only one getting frustrated by
this this problem ...
BTW is this problem only seen on platinumb fb devices? How
is this vram check done for other devices?