Messages in this thread | | | Date | Wed, 26 Mar 2008 13:14:50 +0300 | From | Ivan Kokshaysky <> | Subject | Re: ohci1394 problem (MMIO broken) (was 2.6.25-rc6-git6: Reported regressions from 2.6.24) |
| |
On Tue, Mar 25, 2008 at 02:47:35PM -0700, Linus Torvalds wrote: > On Tue, 25 Mar 2008, Thomas Meyer wrote: > > > > and compare lspci -vv from 2.6.25 and 2.6.24: > > > > 2.6.25: > > > > Region 0: [virtual] Memory at 100000000 (32-bit, non-prefetchable) [size=4K] > > > > 2.6.24: > > > > Region 0: Memory at 8c000000 (32-bit, non-prefetchable) [size=4K] > > Ok, so it didn't use to be at the 4GB mark.
Note that 'Memory at 100000000' is totally bogus as this is 32-bit BAR and respective PCI bridge is 32-bit either.
Most interesting thing is that under 2.6.24 Tomas had
PCI: Bridge: 0000:00:1e.0 IO window: disabled. MEM window: 8c000000-8c0fffff PREFETCH window: disabled.
but with 2.6.25
PCI: Bridge: 0000:00:1e.0 IO window: disabled. MEM window: 0x00000000-0x000fffff PREFETCH window: disabled.
I'm sure that MEM window was actually 0x100000000-0x1000fffff as that printk shows only 8 hex digits.
> This seems to be a PCI and resource alloc issue. It would be really > interesting to see where the 4GB allocation started. Ie ignore anything > else (warnings, driver loadings etc), and _just_ look at lspci -vv output > for where the memory got allocated.
Yeah, it's resource issue for sure. The 00:1e.0 is a transparent bridge, so I blame commit 8fa5913d54f3b1e09948e6a0db34da887e05ff1f (PCI: remove transparent bridge sizing). It's wrong for two reasons: - we cannot ignore standard windows of a transparent bridge as they always positive decode, so they are potential source of address conflicts; - that patch just broke whole bridge setup logic in unpredictable way.
What confused me a lot initially is that the patch was already there in 2.6.24. But I think that issue was somehow masked by 'unsigned longs' used in setup-bus.c all over the place instead of resource_size_t, which has been fixed by Ben in 2.6.25... I think that's why Thomas has everything working again without CONFIG_RESOURCES_64BIT.
Thomas, can you put CONFIG_RESOURCES_64BIT=y back and either revert commit 8fa5913d54f3b1e09948e6a0db34da887e05ff1f, or just comment out these two lines in drivers/pci/setup-bus.c:
if (bus->self->transparent) break;
and check if it helps?
Ivan.
| |