Messages in this thread Patch in this message | | | From | "Luis R. Rodriguez" <> | Subject | [PATCH v3 4/4] video: fbdev: gxt4500: use pci_ioremap_wc_bar() for framebuffer | Date | Tue, 21 Apr 2015 13:20:34 -0700 |
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From: "Luis R. Rodriguez" <mcgrof@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() (see commit de33c442e titled "x86 PAT: fix performance drop for glx, use UC minus for ioremap(), ioremap_nocache() and pci_mmap_page_range()")
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Rob Clark <robdclark@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Suresh Siddha <sbsiddha@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Juergen Gross <jgross@suse.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Airlie <airlied@redhat.com> Cc: Antonino Daplas <adaplas@gmail.com> Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: linux-fbdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@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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