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 | 11 +++++++++++ include/edid.h | 9 +++++++++ 2 files changed, 20 insertions(+)
diff --git a/common/edid.c b/common/edid.c index e41cd3e..e5d35b2 100644 --- a/common/edid.c +++ b/common/edid.c @@ -353,3 +353,14 @@ int edid_dtd_to_fbmode(struct edid_detailed_timing *t,
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; +} diff --git a/include/edid.h b/include/edid.h index d66f76b..b32f42c 100644 --- a/include/edid.h +++ b/include/edid.h @@ -273,4 +273,13 @@ int edid_get_ranges(struct edid1_info *edid, unsigned int *hmin, int edid_dtd_to_fbmode(struct edid_detailed_timing *t, struct fb_videomode *mode, char *name, int name_len);
+/** + * 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); + #endif /* __EDID_H_ */