Why bridge disable VGA_EN?

Kevin B. Hendricks khendricks at ivey.uwo.ca
Mon Nov 19 00:28:34 EST 2001


Okay, I have upgraded to XFree86 CVS HEAD and rebuilt and made a few fixes
for radeon DFP support and now every time I try to use a vgaHW function I
get segfaults.

I have had to literally remove the vgaHW***   functions from the
radeon_driver.c and the X driver works flawlessly (as long as I don't set

I can't figure out why these calls are causing such havoc when my other
card (a Rage128) on bus 0 works flawlessly with these functions.

The radeon is on Bus 1.  I noticed the following in the XFree86 log:

II) Bus 0: bridge is at (0:0:0), (-1,0,0), BCTRL: 0x08 (VGA_EN is set)
(II) Bus 0 I/O range:
        [0] -1  0x00000000 - 0x0000ffff (0x10000) IX[B]
(II) Bus 0 non-prefetchable memory range:
        [0] -1  0x00000000 - 0xffffffff (0x0) MX[B]
(II) Bus 0 prefetchable memory range:
        [0] -1  0x00000000 - 0xffffffff (0x0) MX[B]
(II) Bus 1: bridge is at (0:13:0), (0,1,1), BCTRL: 0x06 (VGA_EN is cleared)
(II) Bus 1 I/O range:
        [0] -1  0x00001000 - 0x000010ff (0x100) IX[B]
        [1] -1  0x00001400 - 0x000014ff (0x100) IX[B]
        [2] -1  0x00001800 - 0x000018ff (0x100) IX[B]
        [3] -1  0x00001c00 - 0x00001cff (0x100) IX[B]

What is the VGA_EN bit and why is it cleared on Bus 1 but enabled on Bus 0?

Is this the cause of my vgaHW problems?

Any help or guidance here would be greatly appreciated.



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