NOT fixed in 5.4.0; it just recurred here on cold start from battery power.

 OS: Ubuntu 20.04 focal
 Kernel: x86_64 Linux 5.4.0-37-generic
 Uptime: 17m
 Packages: 2908
 Shell: bash 5.0.16
 Resolution: 5360x1440
 DE: GNOME 3.36.2
 WM: BudgieWM
 WM Theme: Pocillo
 GTK Theme: Pocillo-dark [GTK2/3]
 Icon Theme: Pocillo
 Font: Noto Sans 11
 Disk: 191G / 412G (49%)
 CPU: AMD Ryzen 7 3700U with Radeon Vega Mobile Gfx @ 8x 2.3GHz
 GPU: AMD RAVEN (DRM 3.35.0, 5.4.0-37-generic, LLVM 9.0.1)
 RAM: 3801MiB / 30049MiB

While sadly this event dashed my hopes that it went away, it also confirmed that the hack from ~alexander-s-m works even with LUKS present.

~vicamo can you please transition status back to confirmed? Not sure what the etiquette here is or if I am supposed to change it myself.

...
Jun 20 20:54:34 redacted kernel: [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout, signaled seq=1, emitted seq=5
Jun 20 20:54:34 redacted kernel: [drm:amdgpu_job_timedout [amdgpu]] *ERROR* Process information: process Xorg pid 1367 thread Xorg:cs0 pid 1387
Jun 20 20:54:34 redacted kernel: amdgpu 0000:05:00.0: GPU reset begin!
Jun 20 20:54:35 redacted kernel: amdgpu 0000:05:00.0: GPU reset succeeded, trying to resume
Jun 20 20:54:35 redacted kernel: [drm] PCIE GART of 1024M enabled (table at 0x000000F400900000).
Jun 20 20:54:35 redacted kernel: [drm] PSP is resuming...
Jun 20 20:54:35 redacted kernel: [drm] reserve 0x400000 from 0xf47f800000 for PSP TMR
Jun 20 20:54:36 redacted kernel: [drm] psp command failed and response status is (0x7)
Jun 20 20:54:36 redacted kernel: [drm] VCN decode and encode initialized successfully(under DPG Mode).
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring gfx uses VM inv eng 0 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring comp_1.0.0 uses VM inv eng 1 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring comp_1.1.0 uses VM inv eng 4 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring comp_1.2.0 uses VM inv eng 5 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring comp_1.3.0 uses VM inv eng 6 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring comp_1.0.1 uses VM inv eng 7 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring comp_1.1.1 uses VM inv eng 8 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring comp_1.2.1 uses VM inv eng 9 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring comp_1.3.1 uses VM inv eng 10 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring kiq_2.1.0 uses VM inv eng 11 on hub 0
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring sdma0 uses VM inv eng 0 on hub 1
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring vcn_dec uses VM inv eng 1 on hub 1
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring vcn_enc0 uses VM inv eng 4 on hub 1
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring vcn_enc1 uses VM inv eng 5 on hub 1
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: ring vcn_jpeg uses VM inv eng 6 on hub 1
Jun 20 20:54:36 redacted kernel: [drm] recover vram bo from shadow start
Jun 20 20:54:36 redacted kernel: [drm] recover vram bo from shadow done
Jun 20 20:54:36 redacted kernel: [drm] Skip scheduling IBs!
Jun 20 20:54:36 redacted kernel: ------------[ cut here ]------------
Jun 20 20:54:36 redacted kernel: WARNING: CPU: 0 PID: 5 at include/linux/dma-fence.h:533 drm_sched_resubmit_jobs+0x152/0x160 [gpu_sched]
Jun 20 20:54:36 redacted kernel: Modules linked in: veth nft_masq nft_chain_nat bridge stp llc zfs(PO) zunicode(PO) zavl(PO) icp(PO) zcommon(PO) znvpair(PO) spl(O) zlua(PO) ebtable_filter ebtables ip6table_raw ip6table_mangle ip6table_nat ip6table_filter ip6_tables iptable_raw iptable_mangle iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_filter bpfilter nf_>
Jun 20 20:54:36 redacted kernel:  ucsi_acpi typec_ucsi typec soundcore mac_hid sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 btrfs xor zstd_compress raid6_pq libcrc32c dm_crypt crct10dif_pclmul crc32_pclmul ghash_clmulni_intel amdgpu rtsx_pci_sdmmc amd_iommu_v2 gpu_sched i2c_algo_bit ttm aesni_intel drm_kms_helper crypto_simd cryptd syscopyarea glue_helper p>
Jun 20 20:54:36 redacted kernel: CPU: 0 PID: 5 Comm: kworker/0:0 Tainted: P           O      5.4.0-37-generic #41-Ubuntu
Jun 20 20:54:36 redacted kernel: Hardware name: LENOVO 20NE000BGE/20NE000BGE, BIOS R11ET36W (1.16 ) 03/30/2020
Jun 20 20:54:36 redacted kernel: Workqueue: events drm_sched_job_timedout [gpu_sched]
Jun 20 20:54:36 redacted kernel: RIP: 0010:drm_sched_resubmit_jobs+0x152/0x160 [gpu_sched]
Jun 20 20:54:36 redacted kernel: Code: 41 5c 41 5d 41 5e 41 5f 5d c3 49 8b 46 10 31 c9 48 c7 80 80 00 00 00 00 00 00 00 49 8b 7f 70 31 c0 83 e7 01 74 04 0f 0b eb bf <0f> 0b eb c7 0f 0b eb 8b 66 0f 1f 44 00 00 0f 1f 44 00 00 55 48 89
Jun 20 20:54:36 redacted kernel: RSP: 0018:ffffbb990010fd28 EFLAGS: 00010246
Jun 20 20:54:36 redacted kernel: RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
Jun 20 20:54:36 redacted kernel: RDX: ffff982911ce1780 RSI: ffff98290e99b9f8 RDI: 0000000000000000
Jun 20 20:54:36 redacted kernel: RBP: ffffbb990010fd60 R08: 00000000000004ec R09: 0000000000000004
Jun 20 20:54:36 redacted kernel: R10: 0000000000000000 R11: 0000000000000001 R12: ffff98290e99e800
Jun 20 20:54:36 redacted kernel: R13: ffff98290b707980 R14: ffff98290e99b800 R15: ffff982911ce1740
Jun 20 20:54:36 redacted kernel: FS:  0000000000000000(0000) GS:ffff982920800000(0000) knlGS:0000000000000000
Jun 20 20:54:36 redacted kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Jun 20 20:54:36 redacted kernel: CR2: 00007ffd73be4798 CR3: 000000078d980000 CR4: 00000000003406f0
Jun 20 20:54:36 redacted kernel: Call Trace:
Jun 20 20:54:36 redacted kernel:  amdgpu_device_gpu_recover+0x6cd/0x95a [amdgpu]
Jun 20 20:54:36 redacted kernel:  amdgpu_job_timedout+0x103/0x130 [amdgpu]
Jun 20 20:54:36 redacted kernel:  drm_sched_job_timedout+0x44/0x90 [gpu_sched]
Jun 20 20:54:36 redacted kernel:  process_one_work+0x1eb/0x3b0
Jun 20 20:54:36 redacted kernel:  worker_thread+0x4d/0x400
Jun 20 20:54:36 redacted kernel:  kthread+0x104/0x140
Jun 20 20:54:36 redacted kernel:  ? process_one_work+0x3b0/0x3b0
Jun 20 20:54:36 redacted kernel:  ? kthread_park+0x90/0x90
Jun 20 20:54:36 redacted kernel:  ret_from_fork+0x22/0x40
Jun 20 20:54:36 redacted kernel: ---[ end trace 1b80cb56eadb79fe ]---
Jun 20 20:54:36 redacted kernel: amdgpu 0000:05:00.0: GPU reset(2) succeeded!
Jun 20 20:54:38 redacted kernel: [drm:amdgpu_cs_ioctl [amdgpu]] *ERROR* Failed to initialize parser -125!
Jun 20 20:54:38 redacted kernel: Bluetooth: RFCOMM TTY layer initialized
Jun 20 20:54:38 redacted kernel: Bluetooth: RFCOMM socket layer initialized
Jun 20 20:54:38 redacted kernel: Bluetooth: RFCOMM ver 1.11
Jun 20 20:54:41 redacted kernel: PM: suspend entry (deep)
...

I wonder if disabling DRM would do any good. If that's possible at all.

Note: Resolution in system information does not reflect boot-time; plugged in the USB-C hub for this post.