[PATCH 1/4] efifb: Enable write-combining

[PATCH 1/4] efifb: Enable write-combining

[Andy Lutomirski]

Running fbcon on an uncached framebuffer is remarkably slow.  So try
to enable write combining in efifb.

Without this patch, it takes 5.8 seconds from efifb probe to i915
probe (default options; no plymouth or quiet mode).  With this patch,
it only takes 1.7 seconds.  That means we wasted over 4 seconds just
writing to UC memory.

Signed-off-by: Andy Lutomirski <luto@mit.edu>
---
 drivers/video/efifb.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/video/efifb.c b/drivers/video/efifb.c
index 4eb38db..a81c944 100644
--- a/drivers/video/efifb.c
+++ b/drivers/video/efifb.c
@@ -413,7 +413,7 @@ static int __devinit efifb_probe(struct platform_device *dev)
 	info->apertures->ranges[0].base = efifb_fix.smem_start;
 	info->apertures->ranges[0].size = size_remap;
 
-	info->screen_base = ioremap(efifb_fix.smem_start, efifb_fix.smem_len);
+	info->screen_base = ioremap_wc(efifb_fix.smem_start, efifb_fix.smem_len);
 	if (!info->screen_base) {
 		printk(KERN_ERR "efifb: abort, cannot ioremap video memory "
 				"0x%x @ 0x%lx\n",
-- 
1.7.5.1

Re: [PATCH 1/4] efifb: Enable write-combining

[Peter Jones]

On 05/26/2011 10:13 AM, Andy Lutomirski wrote:
> Running fbcon on an uncached framebuffer is remarkably slow.  So try
> to enable write combining in efifb.
> 
> Without this patch, it takes 5.8 seconds from efifb probe to i915
> probe (default options; no plymouth or quiet mode).  With this patch,
> it only takes 1.7 seconds.  That means we wasted over 4 seconds just
> writing to UC memory.
> 
> Signed-off-by: Andy Lutomirski <luto@mit.edu>

Looks good:

Signed-off-by: Peter Jones <pjones@redhat.com>


> ---
>  drivers/video/efifb.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/video/efifb.c b/drivers/video/efifb.c
> index 4eb38db..a81c944 100644
> --- a/drivers/video/efifb.c
> +++ b/drivers/video/efifb.c
> @@ -413,7 +413,7 @@ static int __devinit efifb_probe(struct platform_device *dev)
>  	info->apertures->ranges[0].base = efifb_fix.smem_start;
>  	info->apertures->ranges[0].size = size_remap;
>  
> -	info->screen_base = ioremap(efifb_fix.smem_start, efifb_fix.smem_len);
> +	info->screen_base = ioremap_wc(efifb_fix.smem_start, efifb_fix.smem_len);
>  	if (!info->screen_base) {
>  		printk(KERN_ERR "efifb: abort, cannot ioremap video memory "
>  				"0x%x @ 0x%lx\n",


-- 
        Peter

If you're not part of the solution, then you're part of the precipitate.

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