On Thu, 2017-09-07 at 07:22 +0000, Joakim Tjernlund wrote: > On Thu, 2017-09-07 at 17:16 +1000, Benjamin Herrenschmidt wrote: > > On Wed, 2017-09-06 at 15:20 +0000, Joakim Tjernlund wrote: > > > Having problems to mmap PCI UIO devices and stumbeled over this page: > > > http://billfarrow.blogspot.se/2010/09/userspace-access-to-pci-memory.html > > > it claims some adjustments are needed for UIO mmap over PCI to work. > > > These are #if 0 ATM and trying to enable them fails build. > > > > > > Can this be fixed to at least build again ? > > > The reason for having #if 0 in the first place appears to be old X > > > servers, > > > is that still true? Can the special casing be removed now? > > > > This article seems out of date... I *think* things should work without > > change by just mmap'ing the appropriate sysfs files. I'm not sure why > > the author thought that had to be ifdef'ed out... > > Isn't that what the article is doing(mmaping sysfs files)? > And the article author is #ifdefing it back, not out.
Yes sorry that's what I meant. It should work as-is. > > > > Let me know if you have problems. > > Sure, we still are looking > > > > > As far as I know, the generic code will call pci_resource_to_user() > > which on powerpc will return a physical address that already includes > > the offset, which is why we don't later add it. > > > > Now we could probably tear all that out and use the new generic code > > instead as I *think* X has (very) long been fixed but I'd have to spend > > some time triple checking and testing on old HW which I don't have the > > bandwidth for right now. > > Could you fixup the code which is now #if 0 ? I wan't to test the > difference and I not sure how to fix the build problem after changing > those two #if 0 to #if 1 > Even better if they could be a CONFIG option instead. Hrm it's tricky, you shouldn't just turn that ifdef back on without also changing pci_resource_to_user(). I'm not sure exactly what's going on in your case, if you have a problem can you add printk to instrument ? Cheers, Ben.
