On Mon, 4 Nov 2002, Luugi Marsan wrote:

> > > There's a problem when validating a given mode. The board I
> > > have has 256
> > > megs and it fails crying that it has insufficient memory for
> > > the given
> > > mode. This happens because the videoRam in bits is equal to
> > > 2^31 ( 256
> > > megs).  The number passes the numerical limit of an "int". I believe
> > > that the videoRam should be an "unsigned int" instead of a
> > > signed "int".
> > > What do you think? Will this change create other problems?

> > > Y2K all over again. :)

> > sorry, but your number theory has some error.

> > 2^1 = 2 (1 bit, counting from 0 to 1 => 2 values)
> > 2^2 = 4 (2 bits, counting from 0 to 3 => 4 values)
> > 2^4 = 8 (3 bits counting from 0 to 7 => 8 values)
> > [...]
> > 2^31 = 2 GB
> > 2^32 = 4 GB

> > an integer with 32 bits has 1 bit sign and 31 bits for numeric value.
> > this is (-2GB) to (+2GB-1).
> > so your 256 MB limit must arise from somewhere else.

> > for your case you should better starting the printf debugger
> > or real debugging. maybe PCI or AGP config caps, or MTRR caps
> > are the limiting factor, or its just a driver bug. (wild guessing)

> I understand, but 256 megs = 256 * 1024 * 1024* 8 bits = 2^ 31 bits=
> 2147483648. The Xserver calculates the memory in bits when validating
> the mode.

No, it doesn't.  apertureSize is in bytes.

Marc.

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