x86/mm/pat, drivers/media/ivtv: Use arch_phys_wc_add() and require PAT disabled
authorLuis R. Rodriguez <mcgrof@suse.com>
Mon, 15 Jun 2015 08:28:16 +0000 (10:28 +0200)
committerIngo Molnar <mingo@kernel.org>
Thu, 18 Jun 2015 09:23:41 +0000 (11:23 +0200)
commit1bf1735b478008c30acaff18ec6f4a3ff211c28a
tree1ec0bb08cdfbda3ef6258b169182724105e80c5e
parent957561ec0fa8a701f60ca6a0f40cc46f5c554920
x86/mm/pat, drivers/media/ivtv: Use arch_phys_wc_add() and require PAT disabled

We are burrying direct access to MTRR code support on
x86 in order to take advantage of PAT. In the future, we
also want to make the default behavior of ioremap_nocache()
to use strong UC, at which point the use of mtrr_add() on
those systems would make write-combining void.

In order to help both enable us to later make strong
UC default and in order to phase out direct MTRR access
code, port the driver over to the arch_phys_wc_add() API
and annotate that the device driver requires systems to
boot with PAT disabled, with the 'nopat' kernel parameter.

This is a workable compromise given that the hardware is
really rare these days, and perhaps only some lost souls
stuck with obsolete hardware are expected to be using this
feature of the device driver.

Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Walls <awalls@md.metrocast.net>
Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: Stefan Bader <stefan.bader@canonical.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ville Syrjälä <syrjala@sci.fi>
Cc: bhelgaas@google.com
Cc: konrad.wilk@oracle.com
Cc: linux-media@vger.kernel.org
Cc: tomi.valkeinen@ti.com
Cc: toshi.kani@hp.com
Link: http://lkml.kernel.org/r/1434053994-2196-2-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
drivers/media/pci/ivtv/Kconfig
drivers/media/pci/ivtv/ivtvfb.c