[Intel UHD 620 on Linux i915] "HDMI GMBUS EDID read failed"

[f1tz]

Dear all,

Problem: no signal on multiple external monitors via HDMI port, see this thread on Gentoo forums with a moderator here.

Interesting: DisplayPort and Thunderbolt/USB-C work.

Hardware: Intel UHD 620 on-board graphics, https://linux-hardware.org/?probe=ad91e37e92

Software: Linux Kernel 5.11.0 + Gentoo Linux + i915 firmware, Gnome Display Manager + Wayland compositor "sway"

lspci -nnk pastebin: https://dpaste.com/HQAZZ47RD

Kernel .config:  https://dpaste.com/CETSQNVLD 

dmesg: https://dpaste.com/5F7ZPJPLJ 

Approaches for a solution:

1. Which Kernel parameters are necessary for the HDMI port? As miniDisplayPort works, there must be a problem with the bridge?
2. drm : two interesting erros occur, see bold text:
   

[drm:i915_hotplug_work_func] Connector HDMI-A-2 (pin 6) received hotplug event. (retry 0) 
[drm:intel_hdmi_set_edid] HDMI GMBUS EDID read failed, retry using GPIO bit-banging
[drm:drm_do_probe_ddc_edid] drm: skipping non-existent adapter i915 gmbus dpc
[drm:intel_gmbus_force_bit] disabling bit-banging on i915 gmbus dpc. force bit now 0
[drm:do_gmbus_xfer] GMBUS [i915 gmbus dpc] NAK for addr: 0040 w(1)
[drm:do_gmbus_xfer] GMBUS [i915 gmbus dpc] NAK on first message, retry
[drm:do_gmbus_xfer] GMBUS [i915 gmbus dpc] NAK for addr: 0040 w(1)
[drm:drm_dp_dual_mode_detect] DP dual mode HDMI ID:  (err -6)

complete file: https://paste.c-net.org/ReactorKetchup

Thanks for any ideas on how to proceed.

[AndrewG_Intel]

Hello @f1tz

Thank you for posting on the Intel® communities.

We understand that you have some issues/inquiries with Intel® Graphics running on a Linux operating system.

We would like to inform you that Intel does not provide direct downloads and technical support for Linux drivers. The Intel Graphics Linux driver is primarily supported through the original equipment manufacturer (OEM), the Linux distribution vendor, or by the Intel Open Source Technology Center at https://01.org/linuxgraphics. For more information, see the Drivers for Linux document for more details.

For Linux users, we recommend contacting your operating system vendor  (OSV) and use their distribution for driver access and support.

For Linux developers, Intel Graphics Drivers for Linux* are available in source form. The Intel Graphics for Linux site describes other ways you can obtain drivers. For more details, please review these links:

• How to Find Graphics Drivers for Linux*
• Intel® Graphics for Linux*.

If further assistance is needed, we recommend checking further with the OS vendor. Having said that, we will proceed to close this inquiry now from our end, but we will leave the thread open in case other users want to participate.

Thank you for your understanding.

Best regards,

Andrew G.

Intel Customer Support Technician