The
ddc_read_edid() reads a VESA Extended Display Identification Data block (EDID) via VESA Display Data Channel (DDCv2). DDCv2 is a protocol for data exchange between display devices (such as monitors and flat panels) and host machines using an I2C bus.
The
tag argument is a machine-dependent tag used to specify the I2C bus on which the DDCv2 device is located. The
dest argument is a pointer to a buffer where the EDID data will be stored. The
len argument is the amount of data to read into the buffer. (The buffer must be large enough.) Typically, this value will be 128, which is the size of a normal EDID data block.
Normally the EDID data block will be post-processed with the
edid_parse() function.