Bug 706640 - Dealing with broken EDID (CustomEDID option for FLOSS drivers)
Summary: Dealing with broken EDID (CustomEDID option for FLOSS drivers)
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: xorg-x11-drv-nouveau
Version: 20
Hardware: Unspecified
OS: Unspecified
unspecified
medium
Target Milestone: ---
Assignee: Ben Skeggs
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: [cat:RFE]
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2011-05-21 21:06 UTC by Thomas Moschny
Modified: 2018-04-11 17:40 UTC (History)
10 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-06-29 11:36:27 UTC
Type: ---


Attachments (Terms of Use)

Description Thomas Moschny 2011-05-21 21:06:52 UTC
Description of problem:

The second monitor, attached via DVI, remains blank. It is a (bit older) LG Flatron LCD 882, which seems to have problems with the EDID protocol over DVI.


Version-Release number of selected component (if applicable):

xorg-x11-drv-nouveau-0.0.16-24.20110324git8378443.fc15.x86_64
kernel-2.6.38.6-27.fc15.x86_64


Additional info:

dmesg:
[ 2963.328320] [drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 80
[ 2963.328322] [drm:drm_edid_block_valid] *ERROR* Raw EDID:
[ 2963.328325] <3>50 ff ff ff ff ff ff 00 1e 6d 56 46 8f 03 00 00  P........mVF....
[ 2963.328327] <3>08 0b 01 03 8e 24 1d 78 ea 09 20 a2 57 4b 97 24  .....$.x.. .WK.$
[ 2963.328330] <3>18 50 54 a5 6b 80 31 59 45 59 61 59 81 80 01 01  .PT.k.1YEYaY....
[ 2963.328332] <3>01 01 01 01 01 01 30 2a 00 98 51 00 2a 40 30 70  ......0*..Q.*@0p
[ 2963.328334] <3>13 00 67 1f 11 00 00 1e 00 00 00 fd 00 38 55 1e  ..g..........8U.
[ 2963.328336] <3>50 0e 00 0a 20 20 20 20 20 20 00 00 00 fc 00 46  P...      .....F
[ 2963.328339] <3>4c 41 54 52 4f 4e 20 4c 43 44 20 0a 00 00 00 fc  LATRON LCD .....
[ 2963.328341] <3>00 38 38 32 4c 45 20 0a 20 20 20 20 20 20 00 79  .882LE .      .y
[ 2963.328343] 
[ 2963.328346] nouveau 0000:01:00.0: DVI-I-2: EDID block 0 invalid.
[ 2963.328349] [drm] nouveau 0000:01:00.0: DDC responded, but no EDID for DVI-I-2

Some years ago I attached that monitor via VGA, and was able to read and safe a working EDID file:

% xxd /etc/X11/lg.edid   
0000000: 00ff ffff ffff ff00 1e6d 5646 8f03 0000  .........mVF....
0000010: 080b 0103 6e24 1d78 ea09 20a2 574b 9724  ....n$.x.. .WK.$
0000020: 1850 54a5 6b80 3159 4559 6159 8180 0101  .PT.k.1YEYaY....
0000030: 0101 0101 0101 302a 0098 5100 2a40 3070  ......0*..Q.*@0p
0000040: 1300 671f 1100 001e 0000 00fd 0038 551e  ..g..........8U.
0000050: 500e 000a 2020 2020 2020 0000 00fc 0046  P...      .....F
0000060: 4c41 5452 4f4e 204c 4344 200a 0000 00fc  LATRON LCD .....
0000070: 0038 3832 4c45 200a 2020 2020 2020 0099  .882LE .      ..

The two blobs differ at three positions, and the second one has a correct checksum.

Now, using the proprietary driver from nvidia I was able to overcome the monitor's deficiency to properly communicate its EDID via DVI, using the "CustomEDID" option.

Is it possible to use that monitor, connected via DVI, with the nouveau driver by either forcing it to ignore the wrong checksum, or load a custom edid file, or any other means?

Comment 1 Matěj Cepl 2011-05-28 00:30:51 UTC
(In reply to comment #0)
> Now, using the proprietary driver from nvidia I was able to overcome the
> monitor's deficiency to properly communicate its EDID via DVI, using the
> "CustomEDID" option.

You are not the first one to ask for this (bug 517962 ended with the similar request), we should do something about it.

Comment 2 Thomas Moschny 2011-05-28 10:28:12 UTC
For now, I applied the second patch from that bug: https://bugs.freedesktop.org/show_bug.cgi?id=31943 (patch link: https://bugs.freedesktop.org/attachment.cgi?id=41654) to a 2.6.38.7-30.fc15.x86_64 kernel. This allows setting drm.edid_strict=0 on the kernel command line, and now the LG monitor is detected and usable.

So, while the best option would still be to implement a CustomEDID option like in the binary driver, applying at least that small patch would solve the problem for some.

Comment 3 Thomas Moschny 2011-11-16 20:03:12 UTC
Ping. Any news here? Would it be possible to apply the linked patch or a similar one?

Comment 4 Thomas Moschny 2012-04-26 08:45:32 UTC
In fact this needs to be added to the kernel module. The patch mentioned in comment #2 applies to current F16 kernels with minimal fuzz, and works well.

Comment 5 Josh Boyer 2012-04-26 13:30:20 UTC
(In reply to comment #4)
> In fact this needs to be added to the kernel module. The patch mentioned in
> comment #2 applies to current F16 kernels with minimal fuzz, and works well.

We leave GPU bugs assigned to the xorg components.  The same people work on both userspace and kernel, so they can deal with things as they see fit in both.

Comment 6 Fedora End Of Life 2013-01-16 12:25:57 UTC
This message is a reminder that Fedora 16 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
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bug reports from releases that are no longer maintained. At that time
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Comment 7 Thomas Moschny 2013-01-16 14:42:29 UTC
Currently I cannot test that, but maybe the drm.edid_fixup parameter would help here.

Comment 8 Fedora End Of Life 2013-12-21 08:27:55 UTC
This message is a reminder that Fedora 18 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 18. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as WONTFIX if it remains open with a Fedora 
'version' of '18'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version prior to Fedora 18's end of life.

Thank you for reporting this issue and we are sorry that we may not be 
able to fix it before Fedora 18 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior to Fedora 18's end of life.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Comment 9 Fedora End Of Life 2015-05-29 08:39:16 UTC
This message is a reminder that Fedora 20 is nearing its end of life.
Approximately 4 (four) weeks from now Fedora will stop maintaining
and issuing updates for Fedora 20. It is Fedora's policy to close all
bug reports from releases that are no longer maintained. At that time
this bug will be closed as EOL if it remains open with a Fedora  'version'
of '20'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version.

Thank you for reporting this issue and we are sorry that we were not 
able to fix it before Fedora 20 is end of life. If you would still like 
to see this bug fixed and are able to reproduce it against a later version 
of Fedora, you are encouraged  change the 'version' to a later Fedora 
version prior this bug is closed as described in the policy above.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events. Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

Comment 10 Fedora End Of Life 2015-06-29 11:36:27 UTC
Fedora 20 changed to end-of-life (EOL) status on 2015-06-23. Fedora 20 is
no longer maintained, which means that it will not receive any further
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