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authorThomas Schlichter <thomas.schlichter@web.de>2010-11-27 14:17:55 +0100
committerPaul Mundt <lethal@linux-sh.org>2011-03-22 16:20:44 +0900
commit803a4e14a7dceaf01dbc0e02c0fdea2eba4c81b3 (patch)
treeb48aedf2155d355f13cf1607e2ff794244c9050d /drivers/video/vesafb.c
parent7b0e278519eba8050f2b37d7c408958745f30ecd (diff)
uvesafb,vesafb: create WC or WB PAT-entries
with an PAT-enabled kernel, when using uvesafb or vesafb, these drivers will create uncached-minus PAT entries for the framebuffer memory because they use ioremap() (not the *_cache or *_wc variants). When the framebuffer memory intersects with the video RAM used by Xorg, the complete video RAM will be mapped uncached-minus what results in a serve performance penalty. Here are the correct MTRR entries created by uvesafb: schlicht@netbook:~$ cat /proc/mtrr reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back reg01: base=0x06ff00000 ( 1791MB), size= 1MB, count=1: uncachable reg02: base=0x070000000 ( 1792MB), size= 256MB, count=1: uncachable reg03: base=0x0d0000000 ( 3328MB), size= 16MB, count=1: write-combining And here are the problematic PAT entries: schlicht@netbook:~$ sudo cat /sys/kernel/debug/x86/pat_memtype_list PAT memtype list: write-back @ 0x0-0x1000 uncached-minus @ 0x6fedd000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee3000-0x6fee4000 uncached-minus @ 0x6fee3000-0x6fee4000 uncached-minus @ 0x6fee3000-0x6fee4000 uncached-minus @ 0xd0000000-0xe0000000 <-- created by xserver-xorg uncached-minus @ 0xd0000000-0xd1194000 <-- created by uvesafb uncached-minus @ 0xf4000000-0xf4009000 uncached-minus @ 0xf4200000-0xf4400000 uncached-minus @ 0xf5000000-0xf5010000 uncached-minus @ 0xf5100000-0xf5104000 uncached-minus @ 0xf5400000-0xf5404000 uncached-minus @ 0xf5404000-0xf5405000 uncached-minus @ 0xf5404000-0xf5405000 uncached-minus @ 0xfed00000-0xfed01000 Therefore I created the attached patch for uvesafb which uses ioremap_wc() to create the correct PAT entries, as shown below: schlicht@netbook:~$ sudo cat /sys/kernel/debug/x86/pat_memtype_list PAT memtype list: write-back @ 0x0-0x1000 uncached-minus @ 0x6fedd000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee2000-0x6fee3000 uncached-minus @ 0x6fee3000-0x6fee4000 uncached-minus @ 0x6fee3000-0x6fee4000 uncached-minus @ 0x6fee3000-0x6fee4000 write-combining @ 0xd0000000-0xe0000000 write-combining @ 0xd0000000-0xd1194000 uncached-minus @ 0xf4000000-0xf4009000 uncached-minus @ 0xf4200000-0xf4400000 uncached-minus @ 0xf5000000-0xf5010000 uncached-minus @ 0xf5100000-0xf5104000 uncached-minus @ 0xf5400000-0xf5404000 uncached-minus @ 0xf5404000-0xf5405000 uncached-minus @ 0xf5404000-0xf5405000 uncached-minus @ 0xfed00000-0xfed01000 This results in a performance gain, objectively measurable with e.g. x11perf -comppixwin10 -comppixwin100 -comppixwin500: 1: x11perf_xaa.log 2: x11perf_xaa_patched.log 1 2 Operation -------- ---------------- ----------------- 124000.0 202000.0 ( 1.63) Composite 10x10 from pixmap to window 3340.0 24400.0 ( 7.31) Composite 100x100 from pixmap to window 131.0 1150.0 ( 8.78) Composite 500x500 from pixmap to window You can see the serve performance gain when composing larger pixmaps to window. The patches replace the ioremap() function with the variant matching the mtrr- parameter. To create "write-back" PAT entries, the ioremap_cache() function must be called after creating the MTRR entries, and the ioremap_cache() region must completely fit into the MTRR region, this is why the MTRR region size is now rounded up to the next power-of-two. Signed-off-by: Thomas Schlichter <thomas.schlichter@web.de> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'drivers/video/vesafb.c')
-rw-r--r--drivers/video/vesafb.c44
1 files changed, 29 insertions, 15 deletions
diff --git a/drivers/video/vesafb.c b/drivers/video/vesafb.c
index 6a069d04791..a99bbe86db1 100644
--- a/drivers/video/vesafb.c
+++ b/drivers/video/vesafb.c
@@ -303,19 +303,6 @@ static int __init vesafb_probe(struct platform_device *dev)
info->apertures->ranges[0].base = screen_info.lfb_base;
info->apertures->ranges[0].size = size_total;
- info->screen_base = ioremap(vesafb_fix.smem_start, vesafb_fix.smem_len);
- if (!info->screen_base) {
- printk(KERN_ERR
- "vesafb: abort, cannot ioremap video memory 0x%x @ 0x%lx\n",
- vesafb_fix.smem_len, vesafb_fix.smem_start);
- err = -EIO;
- goto err;
- }
-
- printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, "
- "using %dk, total %dk\n",
- vesafb_fix.smem_start, info->screen_base,
- size_remap/1024, size_total/1024);
printk(KERN_INFO "vesafb: mode is %dx%dx%d, linelength=%d, pages=%d\n",
vesafb_defined.xres, vesafb_defined.yres, vesafb_defined.bits_per_pixel, vesafb_fix.line_length, screen_info.pages);
@@ -438,8 +425,7 @@ static int __init vesafb_probe(struct platform_device *dev)
int rc;
/* Find the largest power-of-two */
- while (temp_size & (temp_size - 1))
- temp_size &= (temp_size - 1);
+ temp_size = roundup_pow_of_two(temp_size);
/* Try and find a power of two to add */
do {
@@ -451,6 +437,34 @@ static int __init vesafb_probe(struct platform_device *dev)
}
#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:
+ 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",
+ vesafb_fix.smem_len, vesafb_fix.smem_start);
+ err = -EIO;
+ goto err;
+ }
+
+ printk(KERN_INFO "vesafb: framebuffer at 0x%lx, mapped to 0x%p, "
+ "using %dk, total %dk\n",
+ vesafb_fix.smem_start, info->screen_base,
+ size_remap/1024, size_total/1024);
+
info->fbops = &vesafb_ops;
info->var = vesafb_defined;
info->fix = vesafb_fix;