Using /dev/mem to read video BIOS ROM

Warren Block wblock at
Sun Oct 7 17:41:10 PDT 2007

Following up to my own question:

No, you can't just read a video BIOS ROM directly.  The main video card 
BIOS is at 0xc0000 because it is shadowed there.  To read a BIOS ROM 
directly from the card, you have to enable the ROM and map it into an 
area of memory.

The good news is that Xorg already has routines to do this, and with a 
small fix*, they work correctly on FreeBSD.


-Warren Block * Rapid City, South Dakota USA

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