On Thursday, March 24, 2005 8:54 am, Jesse Barnes wrote:

On Wednesday, March 23, 2005 10:24 pm, Benjamin Herrenschmidt wrote:

quoted

While experimenting with framebuffer access performances, we noticed a
very significant improvement in write access to it when not setting
the "guarded" bit on the MMU mappings. This bit basically says that
reads and writes won't have side effects (it allows speculation). It
appears that it also disables write combining.

Doesn't pgprot_writecombine imply non-guarded, so can't you use it instead?
Either way, you'll probably want to fix fbmem.c as well and turn off
_PAGE_GUARDED?

Nevermind about this bit, I just scrolled a little further into your patch :)

Jesse