Re: [2.1.6?] /proc/pci weirdness

Harald Koenig (koenig@tat.physik.uni-tuebingen.de)
Fri, 14 Nov 1997 10:58:23 +0100


On Nov 13, B. James Phillippe wrote:

> Please forgive me if I'm an idiot, but I'm wondering about the IO
> values listed in /proc/pci. When I boot my system and log in, my video
> card shows this:
>
> Bus 0, device 17, function 0:
> VGA compatible controller: S3 Inc. Trio32/Trio64 (rev 0).
> Medium devsel. IRQ 9.
> Non-prefetchable 32 bit memory at 0xe0000000 [0xe0000000].
>
> Once I've started X, it looks like this (note the IO address):
>
> Bus 0, device 17, function 0:
> VGA compatible controller: S3 Inc. Trio32/Trio64 (rev 0).
> Medium devsel. IRQ 9.
> Non-prefetchable 32 bit memory at 0xf8000000 [0xe0000000].
>
> The above output remains forever, whether I'm in X or not. Once I start
> it, it switches to this and never goes back.

obviously, the X server changed the base address for the card.
as long as everything is working, so what ?

which X server and version are you using ?
XFree86 3.3/3.3.1 shouldn't change this base address for PCI cards
unless you're specifying it in the config file (if you're using
XFree86, please send a full server output).

which Linux kernel version is this, what do these addresses in square brackets mean ?

> I looked at the source to try to figure out what the values represent, but
> I could only minimally make sense of them.

which sources, which values ?

> If someone would be so kind as to enlighten me so that I might understnad
> what process is occuring, I would be most grateful.

the "Non-prefetchable 32 bit memory" address is the start address
at which the frame buffer memory (and registers in some modes)
of the S3 card can be mapped into physical address space.
for some modes of operation ("newmmio" mode for XFree86) this has
to be aligned to 64MB due to S3 hardware constraints.

Harald

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