Add a helper function to check the checksum of an EDID data block.
Signed-off-by: Hans de Goede hdegoede@redhat.com --- common/edid.c | 12 ++++++++++++ include/edid.h | 9 +++++++++ 2 files changed, 21 insertions(+)
diff --git a/common/edid.c b/common/edid.c index e66108f..df797fc 100644 --- a/common/edid.c +++ b/common/edid.c @@ -12,6 +12,7 @@
#include <common.h> #include <edid.h> +#include <errno.h> #include <linux/ctype.h> #include <linux/string.h>
@@ -29,6 +30,17 @@ int edid_check_info(struct edid1_info *edid_info) return 0; }
+int edid_check_checksum(u8 *edid_block) +{ + u8 checksum = 0; + int i; + + for (i = 0; i < 128; i++) + checksum += edid_block[i]; + + return (checksum == 0) ? 0 : -EINVAL; +} + int edid_get_ranges(struct edid1_info *edid, unsigned int *hmin, unsigned int *hmax, unsigned int *vmin, unsigned int *vmax) diff --git a/include/edid.h b/include/edid.h index d3cc523..a69f43a 100644 --- a/include/edid.h +++ b/include/edid.h @@ -246,6 +246,15 @@ void edid_print_info(struct edid1_info *edid_info); int edid_check_info(struct edid1_info *info);
/** + * Check checksum of a 128 bytes EDID data block + * + * @param edid_block EDID block data + * + * @return 0 on success, or a negative errno on error + */ +int edid_check_checksum(u8 *edid_block); + +/** * Get the horizontal and vertical rate ranges of the monitor. * * @param edid The EDID info