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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: 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>
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1 changed files with 35 additions and 0 deletions
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@ -256,6 +256,20 @@ static int atmel_lcdfb_alloc_video_memory(struct atmel_lcdfb_info *sinfo)
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return 0;
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}
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static const struct fb_videomode *atmel_lcdfb_choose_mode(struct fb_var_screeninfo *var,
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struct fb_info *info)
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{
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struct fb_videomode varfbmode;
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const struct fb_videomode *fbmode = NULL;
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fb_var_to_videomode(&varfbmode, var);
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fbmode = fb_find_nearest_mode(&varfbmode, &info->modelist);
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if (fbmode)
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fb_videomode_to_var(var, fbmode);
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return fbmode;
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}
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/**
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* atmel_lcdfb_check_var - Validates a var passed in.
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* @var: frame buffer variable screen structure
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@ -289,6 +303,15 @@ static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
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clk_value_khz = clk_get_rate(sinfo->lcdc_clk) / 1000;
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dev_dbg(dev, "%s:\n", __func__);
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if (!(var->pixclock && var->bits_per_pixel)) {
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/* choose a suitable mode if possible */
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if (!atmel_lcdfb_choose_mode(var, info)) {
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dev_err(dev, "needed value not specified\n");
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return -EINVAL;
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}
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}
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dev_dbg(dev, " resolution: %ux%u\n", var->xres, var->yres);
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dev_dbg(dev, " pixclk: %lu KHz\n", PICOS2KHZ(var->pixclock));
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dev_dbg(dev, " bpp: %u\n", var->bits_per_pixel);
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@ -299,6 +322,13 @@ static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
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return -EINVAL;
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}
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/* Do not allow to have real resoulution larger than virtual */
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if (var->xres > var->xres_virtual)
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var->xres_virtual = var->xres;
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if (var->yres > var->yres_virtual)
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var->yres_virtual = var->yres;
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/* Force same alignment for each line */
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var->xres = (var->xres + 3) & ~3UL;
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var->xres_virtual = (var->xres_virtual + 3) & ~3UL;
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@ -740,6 +770,7 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
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struct fb_info *info;
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struct atmel_lcdfb_info *sinfo;
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struct atmel_lcdfb_info *pdata_sinfo;
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struct fb_videomode fbmode;
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struct resource *regs = NULL;
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struct resource *map = NULL;
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int ret;
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@ -906,6 +937,10 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
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goto free_cmap;
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}
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/* add selected videomode to modelist */
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fb_var_to_videomode(&fbmode, &info->var);
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fb_add_videomode(&fbmode, &info->modelist);
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/* Power up the LCDC screen */
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if (sinfo->atmel_lcdfb_power_control)
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sinfo->atmel_lcdfb_power_control(1);
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