Here may be the interesting dmesg part when running the ATI Radeon 4350 PCI card on the K10 AGP host with Ubuntu 20.04 Focal and Linux 5.10-rc1 kernel. Note that those messages repeats infinitely and very quickly in a way the whole journal becomes full rapidly (dropping earlier entries):

```
[   46.802991] trying to bind memory to uninitialized GART !
[   46.803170] WARNING: CPU: 2 PID: 2610 at drivers/gpu/drm/radeon/radeon_gart.c:297 radeon_gart_bind+0xf1/0x100 [radeon]
[   46.803173] Modules linked in: zram snd_hda_codec_hdmi binfmt_misc snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_usb_audio snd_hda_core snd_usbmidi_lib snd_hwdep edac_mce_amd mc snd_seq_midi snd_pcm snd_seq_midi_event snd_rawmidi snd_seq joydev snd_seq_device snd_timer input_leds kvm_amd snd ccp soundcore kvm k10temp serio_raw mac_hid sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear radeon i2c_algo_bit ttm drm_kms_helper syscopyarea hid_generic sysfillrect sysimgblt fb_sys_fops uas usbhid cec usb_storage hid rc_core psmouse drm forcedeth i2c_nforce2
[   46.803296] CPU: 2 PID: 2610 Comm: gnome-shell Not tainted 5.10.0-051000rc1-generic #202010291359
[   46.803300] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./AM2NF3-VSTA, BIOS P3.20 10/09/2009
[   46.803376] RIP: 0010:radeon_gart_bind+0xf1/0x100 [radeon]
[   46.803383] Code: 00 4c 89 e7 48 8b 40 60 e8 7c 53 3b cd 31 c0 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 c7 c7 48 1a 75 c0 e8 65 90 f6 cc <0f> 0b b8 ea ff ff ff eb dc 66 0f 1f 44 00 00 0f 1f 44 00 00 55 48
[   46.803387] RSP: 0018:ffffb0da81f57a38 EFLAGS: 00010282
[   46.803393] RAX: 0000000000000000 RBX: ffff98801231c6e8 RCX: ffff98832fd18988
[   46.803396] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff98832fd18980
[   46.803400] RBP: ffffb0da81f57a70 R08: 0000000000000000 R09: ffffb0da81f57818
[   46.803403] R10: ffffb0da81f57810 R11: ffffffff8e752ca8 R12: ffff988007a4f580
[   46.803406] R13: ffffb0da81f57b08 R14: ffff988011b19200 R15: ffff98801231c6e8
[   46.803411] FS:  00007f6e1d3dbcc0(0000) GS:ffff98832fd00000(0000) knlGS:0000000000000000
[   46.803415] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   46.803418] CR2: 000055b0490a78f8 CR3: 0000000106534000 CR4: 00000000000006e0
[   46.803421] Call Trace:
[   46.803501]  radeon_ttm_tt_bind+0x7e/0x110 [radeon]
[   46.803519]  ttm_bo_handle_move_mem+0x484/0x4a0 [ttm]
[   46.803534]  ttm_bo_validate+0x137/0x150 [ttm]
[   46.803552]  ttm_bo_init_reserved+0x29f/0x320 [ttm]
[   46.803567]  ttm_bo_init+0x69/0xe0 [ttm]
[   46.803639]  ? radeon_update_memory_usage.isra.0+0x50/0x50 [radeon]
[   46.803712]  radeon_bo_create+0x186/0x200 [radeon]
[   46.803784]  ? radeon_update_memory_usage.isra.0+0x50/0x50 [radeon]
[   46.803859]  radeon_gem_object_create+0xad/0x190 [radeon]
[   46.803934]  ? radeon_gem_pwrite_ioctl+0x30/0x30 [radeon]
[   46.804090]  radeon_gem_create_ioctl+0x69/0x120 [radeon]
[   46.804182]  ? radeon_gem_pwrite_ioctl+0x30/0x30 [radeon]
[   46.804279]  drm_ioctl_kernel+0xae/0xf0 [drm]
[   46.804353]  drm_ioctl+0x245/0x400 [drm]
[   46.804435]  ? radeon_gem_pwrite_ioctl+0x30/0x30 [radeon]
[   46.804452]  ? usb_hcd_irq+0x2c/0x40
[   46.804521]  radeon_drm_ioctl+0x4e/0x80 [radeon]
[   46.804530]  __x64_sys_ioctl+0x91/0xc0
[   46.804537]  do_syscall_64+0x38/0x90
[   46.804546]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
```

I don't see wrong things in dmesg when running the 4.8 kernel on Xenial (while experiencing the same bugs), or they are not obviously wrong enough for me to notice them.