System reports error EDID checksum is invalid, remainder is xxx

Solution Unverified - Updated -

Environment

  • Red Hat Enterprise Linux

Issue

  • Errors like below were noticed:

  • RHEL 9 from /var/log/messages:

Aug  3 00:00:17 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
Aug  3 00:00:27 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
Aug  3 00:00:38 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
Aug  3 00:00:48 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
Aug  3 00:00:58 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
  • RHEL 6 and below: At boot the system scrolls messages similar to the following across the console:
[drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 128
Raw EDID:
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
i915 0000:00:02.0: HDMI-A-2: Ignoring invalid EDID block 59.

Resolution

  • Add parameter nomodeset on kernel command line, reboot the system and check if issue persists:

    • For RHEL 7 and later:
    # grubby --update-kernel=ALL --args='nomodeset'

# reboot

  • Alternatively, disabling only polling also works for the same purposes:

    • For RHEL 7 and later:
    # grubby --update-kernel=ALL --args='drm_kms_helper.poll=0'

# reboot

Root Cause

  • Unlike HDMI, classic VGA has no hotplug detect, so the kernel's drm helper polls every 10 seconds to try to read EDID anyway.
  • EDID is usually stored in the monitor in the firmware chip called serial EEPROM and is accessible via the I²C-bus at address 0x50. The EDID PROM can often be read by the host PC even if the display itself is not attached or turned off.
  • Video mode setting have moved into the kernel. This means that the programming of the hardware specific clock rates and registers on the video card happen in the kernel rather than in the X Windows system starts. On some cards this doesnt work properly. Adding the nomodeset parameter instructs the kernel to use BIOS video modes during boot and load the video drivers when the X Windows system is started.
  • If the EDID checksum invalid messages appear in a setup with no monitor attached, there is no EDID EEPROM, so poll reads return zeros. The checksum then fails each poll, logging the repeated EDID invalid checksum messages.

Diagnostic Steps

  • For RHEL 9: Check for errors like below in /var/log/messages:
Aug  3 00:00:17 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
Aug  3 00:00:27 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
Aug  3 00:00:38 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
Aug  3 00:00:48 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
Aug  3 00:00:58 hostname kernel: EDID block 0 (tag 0x00) checksum is invalid, remainder is 125
  • For RHEL 6 and below: Review console during boot or look at /var/log/dmesg for the following:
[drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 128
Raw EDID:
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
i915 0000:00:02.0: HDMI-A-2: Ignoring invalid EDID block 59.
[drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 128
Raw EDID:
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 128
Raw EDID:
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[drm:drm_edid_block_valid] *ERROR* EDID checksum is invalid, remainder is 128
Raw EDID:
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
    ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff

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