Re: pci-sysfs resource mmap broken (and PATCH)

From: David S. Miller
Date: Thu Apr 28 2005 - 02:33:36 EST

On Thu, 28 Apr 2005 17:21:19 +1000
Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote:

> I have a real net big performance improvement on X by doing that
> trick ... the sysfs mmap API doesn't really provide a mean to do
> it explicitely from userland (unlike the ioctl with the old proc api)

You can refine your test to "if PCI class is display or VGA" and the
prefetchability is set in the BAR, then elide the guard PTE
protection bit.
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