From 968910bd03b226ed410d092c2da59dffe5bfe8de Mon Sep 17 00:00:00 2001 From: Nicolas Ferre Date: Wed, 23 Jul 2008 21:31:34 -0700 Subject: [PATCH] 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 Cc: Haavard Skinnemoen Cc: Andrew Victor Cc: "Antonino A. Daplas" Cc: Krzysztof Helt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/atmel_lcdfb.c | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c index d335bb96b03b..5b3a15dffb5f 100644 --- a/drivers/video/atmel_lcdfb.c +++ b/drivers/video/atmel_lcdfb.c @@ -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); -- 2.20.1