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Re: New User With A Suggestion



On Thu, 2007-03-15 at 22:38 -0400, Jesse Petre wrote:

> The root of all problems came from the X config being installed with a
> default bit-depth of 24-bits.  My monitor does not support 24-bit
> color, only 16 and 32, so after installing Fedora, my monitor would
> simply flash "input not supported".

Nope, sorry.

So there's two phenomena here.  There's color depth, and there's bits
per pixel.  Bits per pixel is how many bits of memory a pixel consumes.
Color depth is how many of those bits are used to represent color
information.  Color depth <= bits per pixel, always.

The normal format we choose is depth 24, 32bpp.  You can also do depth
24, 24bpp, but it's usually much slower since 3/4's of your pixels will
now require unaligned memory accesses.  But there's literally no depth
32 format in the X server.

All of which is sort of besides the point: your monitor never sees any
of this.  If it's VGA, then you're just wiggling analog pins, and the
color depth just reflects the precision with which the pins are wiggled.
If it's a digital connector like DVI-D or laptop-internal LVDS, then the
DVI transmitter pads the color information out to eight bits per color
channel anyway.

So what you actually found was a bug in which we appear to program the
monitor _timings_ wrong in 16bpp, but not in 32bpp.  That's actually
quite interesting, and I would greatly appreciate it if you would file a
bug report with the X logs (/var/log/Xorg.0.log) from attempting to
start at both 16 and 32bpp.

- ajax


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