[PATCH] Use MTRRs by default for vesafb on x86-64

[Andi Kleen]

x86-64 cannot call the 32bit VESA BIOS. This means when vesafb is active
it does software copying in the vesa frame buffer. This is insanely slow
when the frame buffer is not marked for write combining. 

Some discussion showed that the use_mtrr flag was only off for some 
old broken ET4000 ISA card. x86-64 has no ISA, so this is no concern.
Make the default depend on CONFIG_ISA. 

Patch for 2.5.69.  Originally suggested by Gerd Knorr.

-Andi

--- linux/drivers/video/vesafb.c	2003-05-08 04:52:58.000000000 +0200
+++ linux-2.5.69-amd64/drivers/video/vesafb.c	2003-05-15 16:55:51.000000000 +0200
@@ -51,7 +51,11 @@
 static u32 pseudo_palette[17];
 
 static int             inverse   = 0;
+#ifndef CONFIG_ISA 
+static int 	      mtrr	 = 1;
+#else
 static int             mtrr      = 0;
+#endif
 
 static int             pmi_setpal = 0;	/* pmi for palette changes ??? */
 static int             ypan       = 0;  /* 0..nothing, 1..ypan, 2..ywrap */