https://bugzilla.kernel.org/show_bug.cgi?id=204241
--- Comment #64 from felipejfc (fjfcavalcanti@gmail.com) --- (In reply to felipejfc from comment #63)
I'm having the same issue with an AMD RX5700 and kernel version 5.7.9-1 on manjaro linux.
for me adding kernel params 'amd_iommu=on iommu=pt' didn't solve the problem. graphics won't turn on so monitor just keeps blinking
complementing my last answer, the "fix" that worked for me was to disable IOMMU on BIOS