On Thu, Oct 31, 2013 at 10:13:57AM +0100, Thomas Petazzoni wrote: > Sorry for the delay in testing this, I was busy with kernel summit / > ELCE. Unfortunately, this patch still causes problems here: it breaks > usage of I/O region. I have a modified version of the e1000e driver > that makes it access an I/O region, that I have used for testing that > I/O handling is at least minimally working. Without your patch, it > works fine: No problem, thank you for testing it, I don't have any hardware like this.. > After debugging, it turns out that the following change is the problem: > > - if (port->bridge.iolimit < port->bridge.iobase || > + if (port->bridge.iolimit <= port->bridge.iobase || Indeed.. I was having problems here because linux was writing 0,0 during discovery to the base,limit registers to 'disable' the IO window, which triggered a window allocation. So I re-read the PCI bridge spec (apparently too quickly) and decided 0,0 was OK, and it should be <=. However, looking again at the spec - it is very clear, < is the correct test, and when the values is equal a 4k window should be created. So, I wonder if there is a little bug in the Linux discovery code path, should it write FFFF,0 instead? In any event, I can respin this patch so it works, I have to drop the WARN_ON in that routine to accommodate the 0,0 write however. > window is never created and the pci_ioremap_io() function is never > called. Reverting this change makes your patch works fine for me. Great, the next version should be good to go then. Thanks, Jason -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
