[PATCH] video: sm501fb: fixing static checker warning

[PATCH] video: sm501fb: fixing static checker warning

[Heiko Schocher]

Dan Carpenter reported the static checker warning:

drivers/video/fbdev/sm501fb.c:1958 sm501fb_probe()
warn: strcpy() 'cp' of unknown size might be too large for 'fb_mode'

Fix it, as the SM501 datasheet says the SM501 can "200 MHz
DAC support 1280x1024 resolution", which would result in a
too long mode string for current fb_mode var.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
---

 drivers/video/fbdev/sm501fb.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/sm501fb.c b/drivers/video/fbdev/sm501fb.c
index 9e74e8f..ea50df3 100644
--- a/drivers/video/fbdev/sm501fb.c
+++ b/drivers/video/fbdev/sm501fb.c
@@ -43,7 +43,9 @@
 
 #include "edid.h"
 
-static char *fb_mode = "640x480-16@60";
+static char *fb_default_mode = "640x480-16@60";
+static char fb_mode[20];
+static char *fb_mode_cmdline;
 static unsigned long default_bpp = 16;
 
 static struct fb_videomode sm501_default_mode = {
@@ -1963,6 +1965,12 @@ static int sm501fb_probe(struct platform_device *pdev)
 				if (info->edid_data)
 					found = 1;
 			}
+		} else {
+			if (fb_mode_cmdline)
+				strncpy(fb_mode, fb_mode_cmdline,
+					sizeof(fb_mode) - 1);
+			else
+				strcpy(fb_mode, fb_default_mode);
 		}
 #endif
 		if (!found) {
@@ -2230,7 +2238,7 @@ static struct platform_driver sm501fb_driver = {
 
 module_platform_driver(sm501fb_driver);
 
-module_param_named(mode, fb_mode, charp, 0);
+module_param_named(mode, fb_mode_cmdline, charp, 0);
 MODULE_PARM_DESC(mode,
 	"Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\" ");
 module_param_named(bpp, default_bpp, ulong, 0);
-- 
2.1.0

Re: [PATCH] video: sm501fb: fixing static checker warning

[Tomi Valkeinen]

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On 11/06/15 16:13, Heiko Schocher wrote:
> Dan Carpenter reported the static checker warning:
> 
> drivers/video/fbdev/sm501fb.c:1958 sm501fb_probe()
> warn: strcpy() 'cp' of unknown size might be too large for 'fb_mode'
> 
> Fix it, as the SM501 datasheet says the SM501 can "200 MHz
> DAC support 1280x1024 resolution", which would result in a
> too long mode string for current fb_mode var.
> 
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Heiko Schocher <hs@denx.de>
> ---
> 
>  drivers/video/fbdev/sm501fb.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/video/fbdev/sm501fb.c b/drivers/video/fbdev/sm501fb.c
> index 9e74e8f..ea50df3 100644
> --- a/drivers/video/fbdev/sm501fb.c
> +++ b/drivers/video/fbdev/sm501fb.c
> @@ -43,7 +43,9 @@
>  
>  #include "edid.h"
>  
> -static char *fb_mode = "640x480-16@60";
> +static char *fb_default_mode = "640x480-16@60";
> +static char fb_mode[20];
> +static char *fb_mode_cmdline;
>  static unsigned long default_bpp = 16;
>  
>  static struct fb_videomode sm501_default_mode = {
> @@ -1963,6 +1965,12 @@ static int sm501fb_probe(struct platform_device *pdev)
>  				if (info->edid_data)
>  					found = 1;
>  			}
> +		} else {
> +			if (fb_mode_cmdline)
> +				strncpy(fb_mode, fb_mode_cmdline,
> +					sizeof(fb_mode) - 1);
> +			else
> +				strcpy(fb_mode, fb_default_mode);
>  		}
>  #endif

I didn't look at this very closely, but it doesn't look correct to me.
The above code will only be ran if !np. Shouldn't the kernel cmdline
parameter override anything from the .dts?

Then again, that's how it works at the moment, so I guess this is ok.

 Tomi


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