[SRU Trusty] UBUNTU: SAUCE: vesafb: Set mtrr:3 (write-combining) as default

Stefan Bader stefan.bader at canonical.com
Tue Apr 21 12:54:52 UTC 2015


We had this setting from Oneiric to Saucy[1]. In Saucy it was part
of the combined patch to make vesafb a module, which was unnessesary
in Trusty as we moved back to built-in.

It will still be possible to disable mtrr by putting
  video=vesafb:nomtrr or video=vesafb:mtrr:<x>
on the kernel command-line but without that knowledge the default
will be noticably slower (especially on higher resolutions).

[1] https://lists.ubuntu.com/archives/kernel-team/2011-May/015600.html

BugLink: http://bugs.launchpad.net/bugs/1434581

Signed-off-by: Stefan Bader <stefan.bader at canonical.com>
---
 drivers/video/vesafb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/vesafb.c b/drivers/video/vesafb.c
index 1c7da3b..d479804 100644
--- a/drivers/video/vesafb.c
+++ b/drivers/video/vesafb.c
@@ -47,7 +47,7 @@ static struct fb_fix_screeninfo vesafb_fix = {
 };
 
 static int   inverse    __read_mostly;
-static int   mtrr       __read_mostly;		/* disable mtrr */
+static int   mtrr       __read_mostly = 3;	/* enable mtrr write-comb. */
 static int   vram_remap;			/* Set amount of memory to be used */
 static int   vram_total;			/* Set total amount of memory */
 static int   pmi_setpal __read_mostly = 1;	/* pmi for palette changes ??? */
-- 
1.9.1





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