[PATCH edid-decode v2 2/2] Report broken CEA and DisplayID checksums.

[walter harms]

look good for me.

Reviewed-by: wharms at bfs.de

Am 06.02.2017 14:51, schrieb Mark Ferry:
> ---
>  edid-decode.c | 21 ++++++++++++++++++---
>  1 file changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/edid-decode.c b/edid-decode.c
> index 15660dc..95e9c96 100644
> --- a/edid-decode.c
> +++ b/edid-decode.c
> @@ -50,6 +50,8 @@ static int name_descriptor_terminated = 0;
>  static int has_range_descriptor = 0;
>  static int has_preferred_timing = 0;
>  static int has_valid_checksum = 1;
> +static int has_valid_cea_checksum = 1;
> +static int has_valid_displayid_checksum = 1;
>  static int has_valid_cvt = 1;
>  static int has_valid_dummy_block = 1;
>  static int has_valid_week = 0;
> @@ -1289,7 +1291,7 @@ parse_cea(unsigned char *x)
>  		detailed_block(detailed, 1);
>      } while (0);
>  
> -    do_checksum(x, EDID_PAGE_SIZE);
> +    has_valid_cea_checksum = do_checksum(x, EDID_PAGE_SIZE);
>  
>      return ret;
>  }
> @@ -1380,7 +1382,11 @@ parse_displayid(unsigned char *x)
>      int i;
>      printf("Length %d, version %d, extension count %d\n", length, version, ext_count);
>  
> -    do_checksum(x+1, length + 5);
> +    /* DisplayID length field is number of following bytes
> +     * but checksum is calculated over the entire structure
> +     * (excluding DisplayID-in-EDID magic byte)
> +     */
> +    has_valid_displayid_checksum = do_checksum(x+1, length + 5);
>  
>      int offset = 5;
>      while (length > 0) {
> @@ -2048,7 +2054,7 @@ int main(int argc, char **argv)
>  	has_valid_extension_count = 1;
>      }
>  
> -    do_checksum(edid, EDID_PAGE_SIZE);
> +    has_valid_checksum = do_checksum(edid, EDID_PAGE_SIZE);
>  
>      x = edid;
>      for (edid_lines /= 8; edid_lines > 1; edid_lines--) {
> @@ -2142,6 +2148,15 @@ int main(int argc, char **argv)
>  	    printf("\tEDID 1.4 block does not set max dotclock\n");
>      }
>  
> +    if (!has_valid_cea_checksum) {
> +        printf("CEA extension block does not conform\n");
> +        printf("\tBlock has broken checksum\n");
> +    }
> +    if (!has_valid_displayid_checksum) {
> +        printf("DisplayID extension block does not conform\n");
> +        printf("\tBlock has broken checksum\n");
> +    }
> +
>      if (warning_excessive_dotclock_correction)
>  	printf("Warning: CVT block corrects dotclock by more than 9.75MHz\n");
>      if (warning_zero_preferred_refresh)
> 
> 
> 
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