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Fri, 13 Jun 2025 22:26:31 -0700 (PDT) From: Alex Guo To: deller@gmx.de Cc: alexguo1023@gmail.com, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] fbdev: i810 Fix potential divide by zero Date: Sat, 14 Jun 2025 01:26:29 -0400 Message-Id: <20250614052629.3549586-1-alexguo1023@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Variable var->pixclock can be set by user. In case it equals to zero, divide by zero would occur in i810fb_fill_var_timings and i810_get_watermark. We cannot find the default valid value of pixclock for driver i810, so we fix this by returning directly if 'pixclock' is zero. Similar commit: commit 16844e58704 ("video: fbdev: tridentfb: Error out if 'pixclock' equals zero") Signed-off-by: Alex Guo --- drivers/video/fbdev/i810/i810_dvt.c | 2 ++ drivers/video/fbdev/i810/i810_gtf.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/drivers/video/fbdev/i810/i810_dvt.c b/drivers/video/fbdev/i810/i810_dvt.c index 2082b5c92e8f..1db4a63a2631 100644 --- a/drivers/video/fbdev/i810/i810_dvt.c +++ b/drivers/video/fbdev/i810/i810_dvt.c @@ -251,6 +251,8 @@ void i810fb_fill_var_timings(struct fb_var_screeninfo *var) xres = var->xres; yres = var->yres; + if (!var->pixclock) + return; pixclock = 1000000000 / var->pixclock; mode = i810fb_find_best_mode(xres, yres, pixclock); diff --git a/drivers/video/fbdev/i810/i810_gtf.c b/drivers/video/fbdev/i810/i810_gtf.c index 9743d51e7f8c..ae001b256ace 100644 --- a/drivers/video/fbdev/i810/i810_gtf.c +++ b/drivers/video/fbdev/i810/i810_gtf.c @@ -259,6 +259,8 @@ u32 i810_get_watermark(const struct fb_var_screeninfo *var, } } + if (!var->pixclock) + return -EINVAL; pixclock = 1000000/var->pixclock; min = ~0; for (i = 0; i < size; i++) {