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atmel_lcdfb: avoid division by zero

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Avoid division by zero in  atmel_lcdfb_check_var() function.

If pixclock is not specified while passing a var structure in
the check_var() funtion, a division by zero occurs (when
translating pixclock to KHz).

This patch adds a checking of this value and try to choose a
video mode in the modelist.

The mode found in the probe function in added to the modelist.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nicolas Ferre 2008-07-23 21:31:34 -07:00 committed by Linus Torvalds
parent 84c41ce83e
commit 968910bd03
1 changed files with 35 additions and 0 deletions
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35
drivers/video/atmel_lcdfb.c
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@ -256,6 +256,20 @@ static int atmel_lcdfb_alloc_video_memory(struct atmel_lcdfb_info *sinfo)
return 0;
}
static const struct fb_videomode *atmel_lcdfb_choose_mode(struct fb_var_screeninfo *var,
struct fb_info *info)
{
struct fb_videomode varfbmode;
const struct fb_videomode *fbmode = NULL;
fb_var_to_videomode(&varfbmode, var);
fbmode = fb_find_nearest_mode(&varfbmode, &info->modelist);
if (fbmode)
fb_videomode_to_var(var, fbmode);
return fbmode;
}
/**
* atmel_lcdfb_check_var - Validates a var passed in.
* @var: frame buffer variable screen structure
@ -289,6 +303,15 @@ static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
clk_value_khz = clk_get_rate(sinfo->lcdc_clk) / 1000;
dev_dbg(dev, "%s:\n", __func__);
if (!(var->pixclock && var->bits_per_pixel)) {
/* choose a suitable mode if possible */
if (!atmel_lcdfb_choose_mode(var, info)) {
dev_err(dev, "needed value not specified\n");
return -EINVAL;
}
}
dev_dbg(dev, " resolution: %ux%u\n", var->xres, var->yres);
dev_dbg(dev, " pixclk: %lu KHz\n", PICOS2KHZ(var->pixclock));
dev_dbg(dev, " bpp: %u\n", var->bits_per_pixel);
@ -299,6 +322,13 @@ static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
return -EINVAL;
}
/* Do not allow to have real resoulution larger than virtual */
if (var->xres > var->xres_virtual)
var->xres_virtual = var->xres;
if (var->yres > var->yres_virtual)
var->yres_virtual = var->yres;
/* Force same alignment for each line */
var->xres = (var->xres + 3) & ~3UL;
var->xres_virtual = (var->xres_virtual + 3) & ~3UL;
@ -740,6 +770,7 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
struct fb_info *info;
struct atmel_lcdfb_info *sinfo;
struct atmel_lcdfb_info *pdata_sinfo;
struct fb_videomode fbmode;
struct resource *regs = NULL;
struct resource *map = NULL;
int ret;
@ -906,6 +937,10 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
goto free_cmap;
}
/* add selected videomode to modelist */
fb_var_to_videomode(&fbmode, &info->var);
fb_add_videomode(&fbmode, &info->modelist);
/* Power up the LCDC screen */
if (sinfo->atmel_lcdfb_power_control)
sinfo->atmel_lcdfb_power_control(1);