Commit 968910bd authored by Nicolas Ferre's avatar Nicolas Ferre Committed by Linus Torvalds
Browse files

atmel_lcdfb: avoid division by zero 



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: default avatarNicolas 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 84c41ce8

drivers/video/atmel_lcdfb.c

+35 −0
Original line number Diff line number Diff line
@@ -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);

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