Commit-ID:  f3adccbd75831f3651ca6e2cbb83f27cd68a27c9
Gitweb:     http://git.kernel.org/tip/f3adccbd75831f3651ca6e2cbb83f27cd68a27c9
Author:     Luis R. Rodriguez <mcg...@suse.com>
AuthorDate: Mon, 24 Aug 2015 12:13:26 -0700
Committer:  Ingo Molnar <mi...@kernel.org>
CommitDate: Tue, 25 Aug 2015 09:59:44 +0200

drivers/video/fbdev/gxt4500: Use pci_ioremap_wc_bar() to map framebuffer

The driver doesn't use mtrr_add() or arch_phys_wc_add() but
since we know the framebuffer is isolated already on an
ioremap() we can take advantage of write combining for
performance where possible.

In this case there are a few motivations for this:

a) Take advantage of PAT when available.

b) Help with the goal of eventually using _PAGE_CACHE_UC over
   _PAGE_CACHE_UC_MINUS on x86 on ioremap_nocache() (see commit
   de33c442e titled "x86 PAT: fix performance drop for glx,
   use UC minus for ioremap(), ioremap_nocache() and
   pci_mmap_page_range()").

Signed-off-by: Luis R. Rodriguez <mcg...@suse.com>
Signed-off-by: Borislav Petkov <b...@suse.de>
Acked-by: Tomi Valkeinen <tomi.valkei...@ti.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Antonino Daplas <adap...@gmail.com>
Cc: Arnd Bergmann <a...@arndb.de>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
Cc: Dave Airlie <airl...@redhat.com>
Cc: Geert Uytterhoeven <ge...@linux-m68k.org>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Jean-Christophe Plagniol-Villard <plagn...@jcrosoft.com>
Cc: Juergen Gross <jgr...@suse.com>
Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Rob Clark <robdcl...@gmail.com>
Cc: Suresh Siddha <sbsid...@gmail.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: airl...@linux.ie
Cc: b...@kernel.crashing.org
Cc: bhelg...@google.com
Cc: dan.j.willi...@intel.com
Cc: konrad.w...@oracle.com
Cc: linux-fb...@vger.kernel.org
Cc: linux-...@vger.kernel.org
Cc: m...@redhat.com
Cc: toshi.k...@hp.com
Cc: vinod.k...@intel.com
Cc: xen-de...@lists.xensource.com
Link: 
http://lkml.kernel.org/r/1440443613-13696-5-git-send-email-mcg...@do-not-panic.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
 drivers/video/fbdev/gxt4500.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/gxt4500.c b/drivers/video/fbdev/gxt4500.c
index 135d78a..f19133a 100644
--- a/drivers/video/fbdev/gxt4500.c
+++ b/drivers/video/fbdev/gxt4500.c
@@ -662,7 +662,7 @@ static int gxt4500_probe(struct pci_dev *pdev, const struct 
pci_device_id *ent)
 
        info->fix.smem_start = fb_phys;
        info->fix.smem_len = pci_resource_len(pdev, 1);
-       info->screen_base = pci_ioremap_bar(pdev, 1);
+       info->screen_base = pci_ioremap_wc_bar(pdev, 1);
        if (!info->screen_base) {
                dev_err(&pdev->dev, "gxt4500: cannot map framebuffer\n");
                goto err_unmap_regs;
--
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