[CML] dmesg errors [drm:intel_mst_disable_dp] ERROR failed to update payload -22

Submitted by srinivasan.s@intel.com

Assigned to Intel GFX Bugs mailing list

Link to original bug (#111632)

Description

Created attachment 145320
dmesg logs

Steps to Reproduce
===============

1. Connect 2 external monitors to the DUT Via DP MST Hub
   
2. Unplug from the typec end of the DP MST hub of the external monitors and observe this error in the dmesg "[drm:intel_mst_disable_dp] ERROR failed to update payload -22"
   

Expected Result
=============
There must not be any errors in the dmesg

Actual Result
===========
drm error during unplug from the typec end of the DP MST hub of the external monitors "[drm:intel_mst_disable_dp] ERROR failed to update payload -22"

Build versions:
CPU: Intel(R) Core(TM) i5-10210U CPU @ 1.60GHz (8 cores)
Kernel: Linux 5.3.0-rc7-18003-g3ced322fa271 x86_64 (DRM-TIP)

Note:
0. No functionality is getting affected.
1.Though there were these drm messages, there were no distortions in the display (both external monitors and the eDP)
2. This error (ie., "[drm:intel_mst_disable_dp] ERROR failed to update payload -22") is seen when you try to remove the dock itself (which has two external monitors connected via DP cables
3.This error is not seen, when you try to unplug the DP cables (where monitors are connected) from the dock.
4. "No Signal" is seen immediately , when try to unplug the dock.
5. Attached the dmesg logs with the following sequence
adding some markers where you plug and unplug the dock and whether the outputs are ok/not ok after the plug-in like the following:

``
# echo "Plug dock" > /dev/kmsg
``
# echo "Outputs ok/not ok" > /dev/kmsg
# echo "Unplug dock" > /dev/kmsg
``

dmesg > dmesg.log


Solutions:
I would like to propose the following solutions based on my knowledge:

1. Change the print error message to WARNING message
OR
2. Check if the device is not connected, then don't throw this payload error, throw some Warning message else throw this payload error

Thanks,
-Srini

**Attachment 145320**, "dmesg logs":
dmesg.log