lkml.org 
[lkml]   [2005]   [Jan]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Fwd: Patch to control VGA bus routing and active VGA device.
On Fri, Jan 28, 2005 at 12:33:20PM -0700, Grant Grundler wrote:
> > > If it is intended to work with multiple IO Port address spaces,
> > > then it needs to use the pci_dev->resource[] and mangle that appropriately.
> >
> > There is no resource for some of the I/O port space that cards respond to.
>
> Yes - I've heard several graphics cards are horrible broken WRT address
> decoding. Are PCI quirks supposed to handle that sort of thing?

No, PCI quirks are for fixing broken things. VGA cards are entitled to
3c0-3df and all their 10-bit aliases. I've been thinking for a while that we should mark the 10-bit aliases of ISA devices as used ... ie:

x100-x3ff
x500-x7ff
x900-xbff
xd00-xfff

Unfortunately, that may break some legitimate setups, but is hinted at
being a good idea in the EISA docs I've read. My laptop uses only the
10-bit aliases of motherboard space (x000-x0ff, x400-x4ff, x800-x8ff,
xc00-xcff) for devices, except for the ISA bridge, which gets:
1180-11bf : 0000:00:1f.0
1180-11bf : pnp 00:0b
The K6-2 is similar; only 10-bit aliases of motherboard space except for:
0a79-0a79 : isapnp write

Possibly a better solution (less likely to break things) would be to allow
drivers to reserve the 10-bit aliases too. Something like this:

static inline void request_isa_alias_regions(unsigned long start,
unsigned long n, const char *name)
{
int base;
for (base = 0x400; base < 0x10000; base += 0x400) {
request_region(base + start, n, name);
}
}
and then call that in drivers/video/console/vgacon.c

Russell, would that allay your issues with the kernel io resource database?

--
"Next the statesmen will invent cheap lies, putting the blame upon
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince
himself that the war is just, and will thank God for the better sleep
he enjoys after this process of grotesque self-deception." -- Mark Twain
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:09    [from the cache]
©2003-2011 Jasper Spaans