Red Hat Bugzilla – Bug 838265
EDID Checksum Error on Sony VAIO VGN-CR35G
Last modified: 2013-07-31 13:47:33 EDT
Created attachment 596840 [details]
Description of problem:
On system startup, the following lines of text flash on the screen for a split-second:
[ 1.098553] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 31
[ 1.098616] Raw EDID:
[ 1.098667] 36 7f 40 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 1.098721] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 1.098775] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 1.098829] ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 1.098883] ff ff ff ff ff ff ff ff 00 00 00 00 00 00 00 00
[ 1.098937] 00 00 00 00 e0 3b 63 f4 07 00 00 00 20 e9 b5 c0
[ 1.098990] 80 e9 b5 c0 a0 3a b6 c0 80 31 6d f4 50 b6 45 c0
[ 1.099069] 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[ 1.099130] [drm:radeon_atombios_get_lvds_info] *ERROR* Bad LCD record 127
The value of the remainder varies with each boot.
How reproducible: 100%
Steps to Reproduce:
1. Boot Fedora 17
Actual results: The abovementioned error message is displayed
Expected results: No error message is displayed.
Additional info: Identical problem in Fedora 16
Created attachment 596841 [details]
Created attachment 596842 [details]
To my understanding, this is telling you the EDID information in your LCD is broken. It isn't really a kernel problem and just making it go away could be done but it wouldn't actually correct anything.
Adam, is that basically correct?
Thanks for your reply.
As an ordinary user I don't really have a full understanding of EDIDs, but from what I've looked up, I understand that the checksum should add up to 0 for a valid EDID?
It could be that the monitor has an invalid EDID, but, correct me if I'm wrong, in that case, shouldn't I be expecting the same, nonzero checksum result on every boot? I'm actually getting a completely different remainder with each boot, so I thought it might possibly be a problem with the way the EDID is being read.
Thank you for looking into this report.
The error appears to be harmless, in a sense. Your X log shows you using a non-default set of video modes, which indicates that you _are_ getting EDID from somewhere, just not from the code path where that error message is triggered. This makes sense, we check for EDID in multiple places (DDC to the monitor, ACPI, magic BIOS data tables, etc) because it's not found in only one place.
That said, the "EDID block" it's complaining about looks like it could be a chunk of an unrelated BIOS data table, which hints at a bug in the radeon driver's BIOS data table walk code. To verify this, please run the following commands as root:
# echo 1 > /sys/bus/pci/devices/0000:01:00.0/rom
# cp /sys/bus/pci/devices/0000:01:00.0/rom /tmp/rom
And attach the resulting rom file to this bug.
Created attachment 598742 [details]
Thanks for the explanation. Here is the rom dump.
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