I think this belongs here; Vanilla/default Firefox (rpm) installation on up-to-date F39, no rpmfusion (so no hw acceleration). Kernel command line has these added from defaults:
rtc_cmos.use_acpi_alarm=1 amdgpu.sg_display=0
Playing almost any youtube video (this one is fun) will almost immediately result in a journal spam of:
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: [mmhub] page fault (src_id:0 ring:40 vmid:1 pasid:32771, for process RDD Process pid 9117 thread firefox:cs0 pid 10354)
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: in page starting at address 0x0000000000018000 from client 18
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: MMVM_L2_PROTECTION_FAULT_STATUS:0x00143A51
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: Faulty UTCL2 client ID: unknown (0x1d)
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: MORE_FAULTS: 0x1
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: WALKER_ERROR: 0x0
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: PERMISSION_FAULTS: 0x5
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: MAPPING_ERROR: 0x0
Nov 20 13:16:04 angua kernel: amdgpu 0000:c1:00.0: amdgpu: RW: 0x1
Important edit: In addition to the errors, the video (but not the audio) will very visibly stutter and drop frames.
kernel is latest available as of now, 6.5.11-300.fc39.x86_64.