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Commit 80625942 authored by Antonino A. Daplas's avatar Antonino A. Daplas Committed by Linus Torvalds
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[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: default avatarAntonino Daplas <adaplas@pol.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 655a0a77

drivers/video/vesafb.c

+36 −11
Original line number Diff line number Diff line
@@ -45,7 +45,7 @@ static struct fb_fix_screeninfo vesafb_fix __initdata = { 
};



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 *options) 
			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 device *device) 


	if (mtrr) {

		unsigned int temp_size = size_total;

		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 */

		while (temp_size > PAGE_SIZE &&

			mtrr_add(vesafb_fix.smem_start, temp_size, MTRR_TYPE_WRCOMB, 1)==-EINVAL) {

			do {

				rc = mtrr_add(vesafb_fix.smem_start, temp_size,

					      type, 1);

				temp_size >>= 1;

			} while (temp_size >= PAGE_SIZE && rc == -EINVAL);

		}

	}