Originally posted by davec
Thanks for the info. I am using 24 bit, but I thought that the higher color depth was supported.
Is this a card limitation, or an XFree86 limitation?
I think it is just the way things are done.
You specify 24 bits and it logs:
(**) NVIDIA(0): Depth 24, (--) framebuffer bpp 32
(==) NVIDIA(0): RGB weight 888
(==) NVIDIA(0): Default visual is TrueColor
So, apparently it uses 32 bits per pixel in the framebuffer, but there are 24 bits actually in use, 8 per color.
According to xdpyinfo the following depths are supported:
depths (7): 24, 1, 4, 8, 15, 16, 32
So for all purposes except alpha blending it is 32-bit color, it is just called 24 bit in the configuration.
(most 32 bit color modes are really 3x8 bit with maybe an alpha channel for overlaying, but some professional cartds, e.g. for medical purposes, have a 32 bit mode that is 3x10 bits)