Comment 2 for bug 781536

I am affected by this too. I found the following in my dmesg when my computer woke with the external monitor plugged in:

[19519.662971] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 68
[19519.662978] [drm:drm_edid_block_valid] *ERROR* Raw EDID:
[19519.662983] <3>00 ff ff ff ff ff ff 00 5a 63 1c ad 01 01 01 01 ........Zc......
[19519.662986] <3>1b 10 01 03 0e 26 1e 78 2e c5 c6 a3 57 4a 9c 23 .....&.x....WJ.#
[19519.662990] <3>12 4f 54 bf ef 80 81 80 81 40 71 4f 01 01 01 01 .OT......@qO....
[19519.662993] <3>01 01 01 01 01 01 30 2a 00 98 51 00 2a 40 30 70 ......0*..Q.*@0p
[19519.662997] <3>13 00 78 2d 11 00 00 1e 00 00 00 ff 00 50 58 55 ..x-.........PXU
[19519.663000] <3>30 36 32 37 33 31 34 32 30 0a 00 00 00 fd 00 32 062731420......2
[19519.663003] <3>4b 1e 52 0e 00 0a 20 20 20 20 20 20 00 00 00 fc K.R... ....
[19519.663007] <3>00 56 58 39 ff ff ff ff ff ff ff ff ff ff ff ff .VX9............
[19519.663009]
[20030.294769] [drm:drm_mode_getfb] *ERROR* invalid framebuffer id