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Subject[PATCH v3 1/3] video: fbdev: vesafb: only support MTRR_TYPE_WRCOMB
Date
From: "Luis R. Rodriguez" <mcgrof@suse.com>

No other video driver uses MTRR types except for MTRR_TYPE_WRCOMB,
the other MTRR types were implemented and supported here but with
no real good reason. The ioremap() APIs are architecture agnostic and
at least on x86 PAT is a new design that extends MTRRs and
can replace it in a much cleaner way, where so long as the
proper ioremap_wc() or variant API is used the right thing will
be done behind the scenes. This is the only driver left using the
other MTRR types -- and since there is no good reason for it now
rip them out.

Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Suresh Siddha <sbsiddha@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-fbdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
---
drivers/video/fbdev/vesafb.c | 62 ++++++++++++--------------------------------
1 file changed, 16 insertions(+), 46 deletions(-)

diff --git a/drivers/video/fbdev/vesafb.c b/drivers/video/fbdev/vesafb.c
index d79a0ac..191156b 100644
--- a/drivers/video/fbdev/vesafb.c
+++ b/drivers/video/fbdev/vesafb.c
@@ -404,60 +404,30 @@ static int vesafb_probe(struct platform_device *dev)
* region already (FIXME) */
request_region(0x3c0, 32, "vesafb");

+ if (mtrr == 3) {
#ifdef CONFIG_MTRR
- if (mtrr) {
unsigned int temp_size = size_total;
- unsigned int type = 0;
+ int rc;

- 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 */
- temp_size = roundup_pow_of_two(temp_size);
+ /* Find the largest power-of-two */
+ temp_size = roundup_pow_of_two(temp_size);

- /* 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);
- }
- }
+ /* Try and find a power of two to add */
+ do {
+ rc = mtrr_add(vesafb_fix.smem_start, temp_size,
+ MTRR_TYPE_WRCOMB, 1);
+ temp_size >>= 1;
+ } while (temp_size >= PAGE_SIZE && rc == -EINVAL);
#endif
-
- switch (mtrr) {
- case 1: /* uncachable */
- info->screen_base = ioremap_nocache(vesafb_fix.smem_start, vesafb_fix.smem_len);
- break;
- case 2: /* write-back */
- info->screen_base = ioremap_cache(vesafb_fix.smem_start, vesafb_fix.smem_len);
- break;
- case 3: /* write-combining */
info->screen_base = ioremap_wc(vesafb_fix.smem_start, vesafb_fix.smem_len);
- break;
- case 4: /* write-through */
- default:
+ } else {
+#ifdef CONFIG_MTRR
+ if (mtrr && mtrr != 3)
+ WARN_ONCE(1, "Only MTRR_TYPE_WRCOMB (3) make sense\n");
+#endif
info->screen_base = ioremap(vesafb_fix.smem_start, vesafb_fix.smem_len);
- break;
}
+
if (!info->screen_base) {
printk(KERN_ERR
"vesafb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n",
--
2.3.2.209.gd67f9d5.dirty


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