From: Matan Ziv-Av (matan@svgalib.org)
Date: Thu 01 Feb 2001 - 14:15:13 IST
On Wed, 31 Jan 2001, daniel sheltraw wrote:
> To test that my machine supports linear addressing I did a "force chipset"
> to VESA and wrote a SVGAlib program using
> vga_setlinearaddressing() and gl_putbox(). This all worked OK
> so I then tried to write to the VRAM with my kernel module. My
> machine just locked up with a white screen. The address I wrote
> to was that given by phys_to_virt(0xFD000000) which /proc/pci
> says to be prefetchable memory.
That address is not mapped in kernel (or user space processes) memory
space. You need to map it (with ioremap). See how the kernel module (in
svgalib-1.9) does this, and read pci.txt in kernel documentation.
--
Matan Ziv-Av. matan@svgalib.org
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