I confirm I'm also still getting some hangs from time to time. Mostly I think
after a resume from Suspend.

pacman -Q linux linux-firmware {,lib32-}{mesa-git,vulkan-radeon-git,libdrm}

linux 5.3.6.arch1-1
linux-firmware 20190923.417a9c6-1
mesa-git 1:19.3.0_devel.116317.268e0e01f37-1
vulkan-radeon-git 1:19.3.0_devel.116317.268e0e01f37-1
libdrm 2.4.99-1
lib32-mesa-git 1:19.3.0_devel.116317.268e0e01f37-1
lib32-vulkan-radeon-git 1:19.3.0_devel.116317.268e0e01f37-1
lib32-libdrm 2.4.99-1