# i2c adapter: Unable to read EDID block

## mistersnorfles

I get the following error message at boot:

```

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

Non-DDC laptop panel detected

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

i2c_adapter i2c-1: unable to read EDID block

```

First of all, what is i2c and why am I getting this error? Do I actually need i2c for anything? It comes in between messages for radeonfb, so maybe it is related to that?

Second, what is a Non-DDC laptop panel? And should I worry about it not being detected.

I am running 2.6.20 (hardened sources) on a Dell Latitude C640 laptop, if that is of any assistance.

Thanks,

Mr. Snorfles

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## NeddySeagoon

mistersnorfles,

i2c is a general serial interface used by lots of devices to provide set up data.

This particular instance is used by Xorg to read the display capabilities from the display. Normally down the VGA video cable.

Xorg then goes on to set up a format that makes optimal use of the display. This data is called the EDID or DDC data.

Some laptop displays do not support this. The data is included in the BIOS. Thats safe since you don't normally change the display included in a laptop for a different type. Eventually Xorg will look there too. Inculding the data in the BIOS allows some parts to be elimianted, reducing costs.

Most laptops can drive two displays, so you get two sets of status messages (not errors) as Xorg attempts to detect both displays.

The messages do not indicate a problem, its just Xorg telling what its doing.

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