tree 66c6e49c4a24d7338d4510be449e4cc17dc95e29
parent 655a0a7799cddf9a469916c07ac22f1106abc2be
author Antonino A. Daplas <[EMAIL PROTECTED]> Sat, 30 Jul 2005 04:03:31 -0700
committer Linus Torvalds <[EMAIL PROTECTED]> Sat, 30 Jul 2005 05:01:13 -0700

[PATCH] vesafb: Fix mtrr bugs

>> vesafb: mode is 800x600x16, linelength=1600, pages=16
>> vesafb: scrolling: redraw
>> vesafb: Truecolor: size=0:5:6:5, shift=0:11:5:0
>> mtrr: type mismatch for fc000000,1000000 old: write-back new: write-
>> combining

Range is already set to write-back, vesafb attempts to add a write-combining
mtrr (default for vesafb).

>> mtrr: size and base must be multiples of 4 kiB

This is a bug, vesafb attempts to add a size < PAGE_SIZE triggering
the messages below.

To eliminate the warning messages, you can add the option mtrr:2 to add a
write-back mtrr for vesafb.  Or just use nomtrr option.

1. Fix algorithm for finding the best power of 2 size with mtrr_add().

2. Add option to choose the mtrr type by extending the mtrr boot option:

   mtrr:n where n

        0 = no mtrr (equivalent to using the nomtrr option)
        1 = uncachable
        2 = write back
        3 = write combining (default)
        4 = write through

Signed-off-by: Antonino Daplas <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>

 drivers/video/vesafb.c |   47 ++++++++++++++++++++++++++++++++++++-----------
 1 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/drivers/video/vesafb.c b/drivers/video/vesafb.c
--- a/drivers/video/vesafb.c
+++ b/drivers/video/vesafb.c
@@ -45,7 +45,7 @@ static struct fb_fix_screeninfo vesafb_f
 };
 
 static int             inverse   = 0;
-static int             mtrr      = 1;
+static int             mtrr      = 3; /* default to write-combining */
 static int            vram_remap __initdata = 0; /* Set amount of memory to be 
used */
 static int            vram_total __initdata = 0; /* Set total amount of memory 
*/
 static int             pmi_setpal = 0; /* pmi for palette changes ??? */
@@ -204,8 +204,8 @@ static int __init vesafb_setup(char *opt
                        pmi_setpal=0;
                else if (! strcmp(this_opt, "pmipal"))
                        pmi_setpal=1;
-               else if (! strcmp(this_opt, "mtrr"))
-                       mtrr=1;
+               else if (! strncmp(this_opt, "mtrr:", 5))
+                       mtrr = simple_strtoul(this_opt+5, NULL, 0);
                else if (! strcmp(this_opt, "nomtrr"))
                        mtrr=0;
                else if (! strncmp(this_opt, "vtotal:", 7))
@@ -387,14 +387,39 @@ static int __init vesafb_probe(struct de
 
        if (mtrr) {
                unsigned int temp_size = size_total;
-               /* Find the largest power-of-two */
-               while (temp_size & (temp_size - 1))
-                       temp_size &= (temp_size - 1);
-
-               /* Try and find a power of two to add */
-               while (temp_size > PAGE_SIZE &&
-                       mtrr_add(vesafb_fix.smem_start, temp_size, 
MTRR_TYPE_WRCOMB, 1)==-EINVAL) {
-                       temp_size >>= 1;
+               unsigned int type = 0;
+
+               switch (mtrr) {
+               case 1:
+                       type = MTRR_TYPE_UNCACHABLE;
+                       break;
+               case 2:
+                       type = MTRR_TYPE_WRBACK;
+                       break;
+               case 3:
+                       type = MTRR_TYPE_WRCOMB;
+                       break;
+               case 4:
+                       type = MTRR_TYPE_WRTHROUGH;
+                       break;
+               default:
+                       type = 0;
+                       break;
+               }
+
+               if (type) {
+                       int rc;
+
+                       /* Find the largest power-of-two */
+                       while (temp_size & (temp_size - 1))
+                               temp_size &= (temp_size - 1);
+
+                       /* Try and find a power of two to add */
+                       do {
+                               rc = mtrr_add(vesafb_fix.smem_start, temp_size,
+                                             type, 1);
+                               temp_size >>= 1;
+                       } while (temp_size >= PAGE_SIZE && rc == -EINVAL);
                }
        }
        
-
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