From: "Luis R. Rodriguez" <mcg...@suse.com>

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() (de33c442e)

Cc: Suresh Siddha <suresh.b.sid...@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallip...@intel.com>
Cc: Ingo Molnar <mi...@elte.hu>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Juergen Gross <jgr...@suse.com>
Cc: Daniel Vetter <daniel.vet...@ffwll.ch>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Dave Airlie <airl...@redhat.com>
Cc: Antonino Daplas <adap...@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagn...@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkei...@ti.com>
Cc: linux-fb...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcg...@suse.com>
---
 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;
-- 
2.3.2.209.gd67f9d5.dirty

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