Messages in this thread | | | Date | Thu, 19 Apr 2007 16:40:14 -0700 | From | Greg KH <> | Subject | Re: PCI bridge range sizing bug |
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On Thu, Apr 19, 2007 at 04:11:50PM -0700, Jesse Barnes wrote: > On Thursday, April 5, 2007 3:37 pm Adam Jackson wrote: > > So I'm attempting to do something fairly heinous (X server across > > five video cards), and I hit a fun bug in bridge range setup. See > > attached lspci and dmesg, but the short of it is I've got two VGA > > chips on one card behind a bridge, which is itself behind a second > > PCI bridge, and the bridge ranges get set up so that I can't map the > > ROMs, which means I can't post them, and therefore can't use them > > period. > > > > The alignment restriction on the ROMs seems a bit extreme: > > > > % sudo setpci -s 7:2 ROM_ADDRESS=ffffffff > > % sudo setpci -s 7:2 ROM_ADDRESS > > f0000001 > > > > (same for 7:1) so that might be part of the problem. > > ... > Allocating PCI resources starting at 88000000 (gap: 80000000:7ff00000) > ... > > That's ~2G of space, which should be plenty for your PCI resources I > hope? If you have a bunch of cards with large BARS though you might be > running out. > > ... > PCI: Bridge: 0000:00:01.0 > IO window: 4000-4fff > MEM window: a3500000-a35fffff (1M) > PREFETCH window: 90000000-97ffffff > PCI: Bridge: 0000:00:03.0 > IO window: disabled. > MEM window: a3400000-a34fffff (1M) > PREFETCH window: 98000000-9fffffff > PCI: Bridge: 0000:00:1c.0 > IO window: disabled. > MEM window: a3300000-a33fffff (1M) > PREFETCH window: 80000000-8fffffff > PCI: Bridge: 0000:00:1c.4 > IO window: 3000-3fff > MEM window: a3200000-a32fffff (1M) > PREFETCH window: a3700000-a37fffff > PCI: Bridge: 0000:00:1c.5 > IO window: 2000-2fff > MEM window: a3100000-a31fffff (1M) > PREFETCH window: disabled. > PCI: Failed to allocate mem resource #6:10000000@b0000000 for > 0000:07:01.0 > PCI: Failed to allocate mem resource #6:10000000@b0000000 for > 0000:07:02.0 > ... > > Yep, looks like those two devices had a problem. Supposedly they want > to sit at 256M? Given that we're only giving each bridge 1M of memory > space that would definitely be a problem. > > The total so far is only 5M of PCI space... so we're not making good use > of the 2G we were given. > > ... > PCI: Bridge: 0000:06:00.0 > IO window: disabled. > MEM window: a1000000-a2ffffff (32M) > PREFETCH window: disabled. > PCI: Bridge: 0000:00:1e.0 > IO window: 1000-1fff > MEM window: a1000000-a30fffff (~32M) > PREFETCH window: a0000000-a0ffffff > ... > > And these bridges got more space somehow... Greg who's in charge of our > bridge resource allocation code?
Ivan and Linus seem to be doing the most of the work in this area, I gladly pass these issues on to them :)
thanks,
greg k-h - 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/
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