Am Wed, 12 Mar 2008 15:22:59 -0400
thanks for your report. Please CC LKML if you find bugs like this. I
also added Grant Likely (PPC Xilinx Virtex maintainer), as it seems to
Hm, we already mark the page with VM_IO. That's sufficient on x86 and
arm. I'm not sure whether this is a bug in PPC memory handling. Why do
It should be OK, but unneccesary on other platforms. I have no
objections, but I fear in 6 months we'll see a patch removing that
I'd like to hear the opinion of people really involved in PPC memory
Hmmm. I'm not a memory handling expert so I don't know what's going
on here. Josh, does this look like anything that would be ppc405
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
Am Thu, 13 Mar 2008 08:19:32 +0100
I investigated a bit and found your patch to be correct. I cleaned it
up a bit and sent it to Greg and LKML. I added you as author and also
took the freedom to add your Signed-off-by.
Juergen, Thomas, Grant, if you can confirm this, please add your
signature as well.
Am Sun, 16 Mar 2008 03:51:10 +0100
As far as I understood, the VM_IO flag simply means that the page is
used for IO. On some architectures this automatically means that the
page is not cached, but this is not guaranteed. That's why
If I misunderstood something or somebody can explain it better, please
It _is_ trivial. It's just something you don't need every day, and
therefore it's not known to everybody (including me) or not obvious.
But if you look at it:
VM_IO means IO
pgprot_noncached means noncached
What could be more trivial?