# "EDID chceksum is invalid" - kernel messages

## GENERiCfr

I've got a problem with a radeon driver(I think). From time to time there are many messages in dmesg, such as: "i2c i2c-0:sendbytes: NAK bailout.", "[drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 199." and "Raw EDID: 0f ff ff ff...(the value is changing every output)". Also sometimes my screen goes black for a while.

I didn't have any problems with it past. I just reinstalled gentoo and  compiled 3.2.1 kernel(earlier I had 3.0.6). I thought that this is kernel specific, so I emerged 3.1.10, but nothing changes. 

PS: I just realized that it only happens when I'm on the console.

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## PaddyMac

When you type dmesg, your kernel message log is probably flooded with messages like this, right?

```

[ 5727.667635] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 188

[ 5727.667640] Raw EDID:

[ 5727.667645]          00 ff ff ff ff ff ff 00 ff ff 0f 51 4c 48 31 31

[ 5727.667648]          33 0a 01 02 0e 21 18 96 eb 0c c9 a0 57 47 9b 27

[ 5727.667650]          12 48 4c a4 43 00 61 59 45 59 a9 40 31 59 01 01

[ 5727.667653]          01 01 01 01 01 01 c3 1e 00 20 41 00 20 30 10 60

[ 5727.667655]          13 00 38 ea 10 00 00 1e 00 00 00 ff 00 36 32 37

[ 5727.667658]          31 52 30 43 42 31 31 48 4c 0a 00 00 00 fc 00 44

[ 5727.667660]          45 4c 4c 20 50 37 38 30 0a 20 20 20 00 00 00 fd

[ 5727.667663]          00 30 78 1e 55 ff 00 0a 20 20 20 20 20 20 00 7f

[ 5727.667670] radeon 0000:01:00.0: VGA-1: EDID block 0 invalid.

[ 5727.667678] [drm:radeon_vga_detect] *ERROR* VGA-1: probed a monitor but no|invalid EDID

```

This is a known issue with radeon driver and KMS. For the time being, you either A) Have to live with it until it's fixed (don't hold your breath) or B) disable KMS and use UMS. KMS is faster than UMS, and you'll generally see overall better performance, but you'll also see problems like the one above and that automatic monitor detection is faulty, or maybe even some graphics errors. You can disable KMS with a radeon card by passing radeon.modeset=0 to your kernel. At least this is the case with the open source driver. Your mileage may differ if you are using or wish to try using the proprietary ATI driver. I also have an old ATI Radeon 9200 card and have pretty much just learned to live with it until Radeon/KMS issues are resolved.

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## Hu

Clarification: it is a known issue when using Radeon, KMS, and devices that have bad EDID data.  I have Radeon-based systems that do not show that message (and also do not exhibit any particular problems in normal usage).

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## GENERiCfr

Hmm...I'll try to live with it, but it's little annoying when I'm on console(once the screen went black every 10 seconds). But I was surprised that on 3.0.6 kernel everything was fine(at least I didn't noticed any problems). Thanks for clearing that up, guys. ;]

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