Re: mtrr and xf86 confusion?

From: Rogier Wolff (R.E.Wolff@BitWizard.nl)
Date: Thu Jun 01 2000 - 03:11:23 EST


H. Peter Anvin wrote:
> Followup to: <Pine.LNX.4.21.0005311410560.1610-100000@badlands.lexington.ibm.com>
> By author: Richard A Nelson <cowboy@vnet.ibm.com>
> In newsgroup: linux.dev.kernel
> >
> > I get this from the xdm log:
> > ...
> > (--) SVGA: PCI: S3 Savage4 rev 2, Memory @ 0xfeb80000, 0xf0000000
> > (--) SVGA: SAVAGE: Savage4 rev 2, Linear FB @ 0xfeb80000
> > (--) SVGA: Detected S3 Savage4
> > (--) SVGA: using driver for chipset "s3_savage"
> > (--) SVGA: videoram: 8192k
> > (--) SVGA: Ramdac speed: 250 MHz (220 MHz for 32 bpp)
> > (--) SVGA: Detected current MCLK value of 109.773 MHz
> > (--) SVGA: VBE Version 2.0
> > (--) SVGA: BIOS label is "S3 Incorporated. Savage4"
> > ...
> >
> > But, I can't set the mtrr as per /usr/src/linux/Documentation/mtrr.txt:
> > echo "base=0xfeb80000 size=0x800000 type=write-combining" > /proc/mtrr
> > kernel: mtrr: base(0xfeb80000) is not aligned on a size(0x800000) boundary
> >
>
> You have a zero too much in your "size=" argument.

Huh? His 800000 equals the 8Mb of memory that his video card has.
Sounds good to me.

Yes, it's odd that someone would align an 8Mb memory buffer at
0xfeb80000. This is nowhere near an 8Mb boundary.

If I read the above log correlclty the chip has two windows. One at
0xf0000000, no larger than 256Mb and one at 0xfeb80000 no larger than
half a meg.

The second line of the log may well miss-print the "linear FB @"
number. It's probably 0xf0000000. If the rest works, the print on the
second line is wrong/old. The Linear buffer is at 0xf0000000.

                                Roger.

-- 
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 **
*-- BitWizard writes Linux device drivers for any device you may have! --*
*       Common sense is the collection of                                *
******  prejudices acquired by age eighteen.   -- Albert Einstein ********

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