I am on an Intel(R) Core(TM)2 Duo CPU T5450 @ 1.66GHz laptop, running Debian 10.1 i686 with a custom-compiled 5.4.0-rc6 kernel (config attached). The laptop has a Radeon video card; the relevant output of 'lspci -k' is

01:05.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RC410M [Mobility Radeon Xpress 200M] Subsystem: ASUSTeK Computer Inc. RC410M [Mobility Radeon Xpress 200M] Kernel driver in use: radeon Kernel modules: radeon

rc6 is giving me traces in dmesg complaining about drm_vblank (the trace is attached). The issue was not present in rc5.

I am sending the message to the addresses listed in the MAINTAINERS file of the current Linux tree under the headings

DRM DRIVERS DRM DRIVERS AND MISC GPU PATCHES RADEON and AMDGPU DRM DRIVERS

apologies if this is overly broad.