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EDID(9) Kernel Developer's Manual EDID(9) NAME edid - VESA Extended Display Identification Data SYNOPSIS #include <dev/videomode/videomode.h> #include <dev/videomode/edidvar.h> #include <dev/videomode/edidreg.h> int edid_is_valid(uint8_t *data); int edid_parse(uint8_t *data, struct edid_info *info); void edid_print(struct edid_info *info); DESCRIPTION These functions provide support parsing the Extended Display Identification Data which describes a display device such as a monitor or flat panel display. The edid_is_valid() function simply tests if the EDID block in data contains valid data. This test includes a verification of the checksum, and that valid vendor and product idenfication data is present. The data block contain at least 128 bytes. The edid_parse() function parses the supplied data block (which again, must be at least 128 bytes), writing the relevant data into the structure pointed to by info. The edid_print() function prints the data in the given info structure to the console device. RETURN VALUES The edid_is_valid() function returns 0 if the data block is valid, and EINVAL otherwise. The edid_parse() function returns zero if the data was successfully parsed, and non-zero otherwise. EXAMPLES The following code uses these functions to retrieve and print information about a monitor: struct edid_info info; i2c_tag_t tag; char buffer; ... /* initialize i2c tag... */ ... if ((ddc_read_edid(tag, buffer, 128) == 0) && (edid_parse(buffer, &info) == 0)) edid_print(&info); ... CODE REFERENCES The EDID subsystem is implemented within the file sys/dev/videomode/edid.c. The EDID subsystem also makes use of VESA Generalized Timing Formula located located in sys/dev/videomode/vesagtf.c and the generic videomode database located in sys/dev/videomode/videomode.c. SEE ALSO ddc(9), iic(9) HISTORY These routines were added in NetBSD 4.0. AUTHORS Garrett D'Amore <gdamore@NetBSD.org> NetBSD 8.0 July 24, 2013 NetBSD 8.0