EDID(9) 						   BSD Kernel Developer's Manual						   EDID(9)

NAME

     edid -- VESA Extended Display Identification Data

SYNOPSIS

     #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 struc-
     ture 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.

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.

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[128];

	     ...
	     /* initialize i2c tag... */
	     ...
	     if ((ddc_read_edid(tag, buffer, 128) == 0) &&
		 (edid_parse(buffer, &info) == 0))
		     edid_print(info);
	     ...

SEE ALSO

     ddc(9), iic(9)

HISTORY

     These routines were added in NetBSD 4.0.

AUTHORS

     Garrett D'Amore <gdamore@NetBSD.org>

BSD
								   May 11, 2006 							       BSD