I can confirm that reverting to linux-firmware:amd64=1.173.12 with kernel 5.3.0-40-generic on Xubuntu 18.04.4 solved my problem.
Workaround with kernel parameter "radeon.modeset=0 rd.driver.blacklist=radeon" removed error messages but caused fan to work constantly when watching e. g. youtube in chrome.
Using Samsung ativbook 730U3E with display controller: Advanced Micro Devices, Inc. [AMD/ATI] Mars [Radeon HD 8730M]
I can confirm that reverting to linux-firmware: amd64=1. 173.12 with kernel 5.3.0-40-generic on Xubuntu 18.04.4 solved my problem.
Workaround with kernel parameter "radeon.modeset=0 rd.driver. blacklist= radeon" removed error messages but caused fan to work constantly when watching e. g. youtube in chrome.
Using Samsung ativbook 730U3E with display controller: Advanced Micro Devices, Inc. [AMD/ATI] Mars [Radeon HD 8730M]
Regards
Peter