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* [PATCH] atmel_lcdfb: fix negative check on unsigned
@ 2008-04-17  4:31 Roel Kluin
  2008-04-19  2:34 ` Haavard Skinnemoen
  0 siblings, 1 reply; 2+ messages in thread
From: Roel Kluin @ 2008-04-17  4:31 UTC (permalink / raw)
  To: hskinnemoen, lkml

No signed negative values will get noticed

Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
---
diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c
index fc65c02..4b927da 100644
--- a/drivers/video/atmel_lcdfb.c
+++ b/drivers/video/atmel_lcdfb.c
@@ -422,13 +422,13 @@ static int atmel_lcdfb_set_par(struct fb_info *info)
 
 	value = DIV_ROUND_UP(clk_value_khz, PICOS2KHZ(info->var.pixclock));
 
-	value = (value / 2) - 1;
-	dev_dbg(info->device, "  * programming CLKVAL = 0x%08lx\n", value);
-
-	if (value <= 0) {
+	if ((value / 2) <= 1) {
+		dev_dbg(info->device, "  * programming CLKVAL = 0x%08lx\n", (value/2)-1);
 		dev_notice(info->device, "Bypassing pixel clock divider\n");
 		lcdc_writel(sinfo, ATMEL_LCDC_LCDCON1, ATMEL_LCDC_BYPASS);
 	} else {
+		value = (value / 2) - 1;
+		dev_dbg(info->device, "  * programming CLKVAL = 0x%08lx\n", value);
 		lcdc_writel(sinfo, ATMEL_LCDC_LCDCON1, value << ATMEL_LCDC_CLKVAL_OFFSET);
 		info->var.pixclock = KHZ2PICOS(clk_value_khz / (2 * (value + 1)));
 		dev_dbg(info->device, "  updated pixclk:     %lu KHz\n",

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH] atmel_lcdfb: fix negative check on unsigned
  2008-04-17  4:31 [PATCH] atmel_lcdfb: fix negative check on unsigned Roel Kluin
@ 2008-04-19  2:34 ` Haavard Skinnemoen
  0 siblings, 0 replies; 2+ messages in thread
From: Haavard Skinnemoen @ 2008-04-19  2:34 UTC (permalink / raw)
  To: Roel Kluin; +Cc: lkml, Nicolas Ferre

Cc'ing the atmel_lcdfb maintainer...

On Thu, 17 Apr 2008 06:31:28 +0200
Roel Kluin <12o3l@tiscali.nl> wrote:

> No signed negative values will get noticed
> 
> Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
> ---
> diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c
> index fc65c02..4b927da 100644
> --- a/drivers/video/atmel_lcdfb.c
> +++ b/drivers/video/atmel_lcdfb.c
> @@ -422,13 +422,13 @@ static int atmel_lcdfb_set_par(struct fb_info *info)
>  
>  	value = DIV_ROUND_UP(clk_value_khz, PICOS2KHZ(info->var.pixclock));
>  
> -	value = (value / 2) - 1;
> -	dev_dbg(info->device, "  * programming CLKVAL = 0x%08lx\n", value);
> -
> -	if (value <= 0) {
> +	if ((value / 2) <= 1) {
> +		dev_dbg(info->device, "  * programming CLKVAL = 0x%08lx\n", (value/2)-1);

Makes sense...although I think there's another patch in the queue that
fixes this as well.

>  		dev_notice(info->device, "Bypassing pixel clock divider\n");
>  		lcdc_writel(sinfo, ATMEL_LCDC_LCDCON1, ATMEL_LCDC_BYPASS);
>  	} else {
> +		value = (value / 2) - 1;
> +		dev_dbg(info->device, "  * programming CLKVAL = 0x%08lx\n", value);
>  		lcdc_writel(sinfo, ATMEL_LCDC_LCDCON1, value << ATMEL_LCDC_CLKVAL_OFFSET);
>  		info->var.pixclock = KHZ2PICOS(clk_value_khz / (2 * (value + 1)));
>  		dev_dbg(info->device, "  updated pixclk:     %lu KHz\n",

Haavard

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2008-04-17  4:31 [PATCH] atmel_lcdfb: fix negative check on unsigned Roel Kluin
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