"EDID checksum is invalid"

[Keith Packard]

Robert Morell <rmorell at nvidia.com> writes:

> FWIW, I've seen that exact symptom on some monitors when the +5V pin on
> the DVI or HDMI cable from the GPU isn't enabled (or isn't providing
> enough current).  Some monitors power the i2c/edid/DDC logic from that
> +5V either exclusively or when in the DPMS off state, and the i2c chip
> will just stop responding after a few cycles if not provided sufficient
> power.

Makes sense -- the chip will power itself from the i2c when not
transmitting, and can talk until whatever energy is stored in various
capacitors on the Vcc rail discharge.

-- 
-keith
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