Thread (31 messages) flat view 31 messages, 7 authors, 2015-05-20

Re: [PATCH v3 16/17] video: fbdev: atmel_lcdfb: use ioremap_wc() for framebuffer

From: Nicolas Ferre <hidden>
Date: 2015-04-22 07:35:08
Also in: cocci, lkml

Le 21/04/2015 22:16, Luis R. Rodriguez a écrit :
From: "Luis R. Rodriguez" <redacted>

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: Nicolas Ferre <redacted>
Seems okay:
Acked-by: Nicolas Ferre <redacted>

Thanks for having taking care of atmel_lcdfb driver.
Bye,

quoted hunk ↗ jump to hunk
Cc: Suresh Siddha <redacted>
Cc: Ingo Molnar <redacted>
Cc: Thomas Gleixner <redacted>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <redacted>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <redacted>
Cc: Tomi Valkeinen <redacted>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <redacted>
---
 drivers/video/fbdev/atmel_lcdfb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/video/fbdev/atmel_lcdfb.c b/drivers/video/fbdev/atmel_lcdfb.c
index 94a8d04..abadc49 100644
--- a/drivers/video/fbdev/atmel_lcdfb.c
+++ b/drivers/video/fbdev/atmel_lcdfb.c
@@ -1266,7 +1266,8 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
 			goto stop_clk;
 		}
 
-		info->screen_base = ioremap(info->fix.smem_start, info->fix.smem_len);
+		info->screen_base = ioremap_wc(info->fix.smem_start,
+					       info->fix.smem_len);
 		if (!info->screen_base) {
 			ret = -ENOMEM;
 			goto release_intmem;

-- 
Nicolas Ferre
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