• Luis R. Rodriguez's avatar
    x86/mm/pat, drivers/media/ivtv: Use arch_phys_wc_add() and require PAT disabled · 1bf1735b
    Luis R. Rodriguez authored
    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: default avatarLuis R. Rodriguez <mcgrof@suse.com>
    Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
    Acked-by: default avatarAndy Walls <awalls@md.metrocast.net>
    Acked-by: default avatarMauro 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.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    1bf1735b
ivtvfb.c 36 KB