Comment 0 for bug 712075

Recently, with .37-12 (.38 is so unstable generally that I can't run it long enough to see if it's a problem there), X will flicker, and I'll see forms of this in dmesg:

[159746.098380] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 85
[159746.098384] [drm:drm_edid_block_valid] *ERROR* Raw EDID:
[159746.098387] <3>00 ff ff ff ff ff ff 00 10 ac 15 f0 4c 36 43 34 ............L6C4
[159746.098389] <3>21 14 01 03 80 34 20 78 ee 1e c5 af ff ff ff ff !....4 x........
[159746.098391] <3>ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
[159746.098393] <3>ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
[159746.098394] <3>ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
[159746.098396] <3>ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
[159746.098398] <3>ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
[159746.098400] <3>ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
[159746.098401]

Sometimes I also see:

[163776.033364] i2c i2c-10: sendbytes: NAK bailout.

And then, about every 2 days, video signal is not restored after one of these flickers, and the monitor stays dark. This is successful:

  sudo get-edid

Swapping cables does not change it. Swapping monitors does not change it. In fact, changing monitors actually triggers the kernel to re-request edid, which fails with each new monitor attached, where as "sudo get-edid" has no problem. So this does not appear to be motherboard, cable, or monitor related. Something in the kernel DRM is breaking and not recovering, as far as I can tell.