Created attachment 1729336 [details]
File: dmesg

At this moment I have determined it is reproducible.

I have two monitors of the same model (Dell U2414H) connected using Displayport to my graphics card. When I boot with 1 monitor on everything is fine and keeps working, the moment I enable the second monitor the graphics stop working, at first the mouse keeps moving as I touch it, but clicking windows or using the keyboard yields no graphical results. After a while the mouse stops working as well and when I ssh in the machine I see a similar dmesg trace.

If I boot the machine with both monitors enabled I do not get any screen output and sshing into the machine yields the same dmesg trace. 

The same behavior occurs when I daisy chain the monitors or when I plug them both directly in the gpu. And the same occurs when I use HDMI to connect 1 screen and Displayport to connect the second.

Same behavior still occurs on Kernel 5.9.9

dmesg output:

[  666.448682] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  666.448789] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  666.448890] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  666.448988] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  666.449085] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  686.608504] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  686.608611] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  686.608712] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  686.608810] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  686.608906] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  707.280307] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  707.280415] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  707.280516] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  707.280614] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  707.280711] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  728.720229] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  728.720350] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  728.720457] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  728.720556] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  728.720663] [drm:amdgpu_dm_connector_mode_valid [amdgpu]] *ERROR* dc_sink is NULL!
[  733.712052] ------------[ cut here ]------------
[  733.712054] kernel BUG at drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:8054!
[  733.712062] invalid opcode: 0000 [#1] SMP NOPTI
[  733.712065] CPU: 7 PID: 2249 Comm: Xorg Not tainted 5.9.9-200.fc33.x86_64 #1
[  733.712066] Hardware name: Micro-Star International Co., Ltd. MS-7B89/B450M MORTAR MAX (MS-7B89), BIOS 2.80 06/10/2020
[  733.712180] RIP: 0010:dm_update_crtc_state+0x5aa/0x700 [amdgpu]
[  733.712182] Code: c0 bf 02 00 00 00 48 c7 c6 e0 f0 a6 c0 e8 5e 24 d2 ff b8 f4 ff ff ff e9 a1 fb ff ff 4d 85 d2 0f 85 7d fb ff ff e9 91 fb ff ff <0f> 0b 49 8b b3 78 01 00 00 4c 89 d7 e8 d5 9e 12 00 4c 8b 54 24 10
[  733.712184] RSP: 0018:ffffa19588a8bad8 EFLAGS: 00010246
[  733.712186] RAX: ffff8c1ddf9cb001 RBX: ffff8c1ead5ef000 RCX: 0000000000001fd5
[  733.712187] RDX: 0000000000001fd4 RSI: cf33a87491252d49 RDI: 000000000002f180
[  733.712188] RBP: ffff8c1ea9e07000 R08: ffff8c1edf355ef8 R09: ffff8c1edf355ef8
[  733.712189] R10: ffff8c1ddf9ca000 R11: 0000000000000006 R12: ffff8c1eb7fd6c00
[  733.712190] R13: 0000000000000000 R14: 0000000000000001 R15: ffff8c1e3238de00
[  733.712192] FS:  00007f30bafb5a80(0000) GS:ffff8c1ebe9c0000(0000) knlGS:0000000000000000
[  733.712193] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  733.712194] CR2: 00007f3066b6f000 CR3: 0000000721844000 CR4: 0000000000350ee0
[  733.712195] Call Trace:
[  733.712306]  amdgpu_dm_atomic_check+0x320/0x1020 [amdgpu]
[  733.712327]  ? drm_property_replace_global_blob+0xe0/0xe0 [drm]
[  733.712330]  ? _cond_resched+0x16/0x40
[  733.712332]  ? __ww_mutex_lock.constprop.0+0x22/0x710
[  733.712333]  ? _cond_resched+0x16/0x40
[  733.712337]  ? slab_pre_alloc_hook.constprop.0+0xd0/0x110
[  733.712355]  drm_atomic_check_only+0x55a/0x7d0 [drm]
[  733.712370]  drm_atomic_commit+0x13/0x50 [drm]
[  733.712381]  drm_atomic_helper_set_config+0x70/0xb0 [drm_kms_helper]
[  733.712397]  drm_mode_setcrtc+0x1d3/0x6f0 [drm]
[  733.712401]  ? avc_has_extended_perms+0x4f/0x3d0
[  733.712415]  ? drm_mode_getcrtc+0x180/0x180 [drm]
[  733.712430]  drm_ioctl_kernel+0x86/0xd0 [drm]
[  733.712445]  drm_ioctl+0x20f/0x3a0 [drm]
[  733.712459]  ? drm_mode_getcrtc+0x180/0x180 [drm]
[  733.712537]  amdgpu_drm_ioctl+0x49/0x80 [amdgpu]
[  733.712541]  __x64_sys_ioctl+0x83/0xb0
[  733.712543]  do_syscall_64+0x33/0x40
[  733.712546]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  733.712548] RIP: 0033:0x7f30bb52738b
[  733.712550] Code: 89 d8 49 8d 3c 1c 48 f7 d8 49 39 c4 72 b5 e8 1c ff ff ff 85 c0 78 ba 4c 89 e0 5b 5d 41 5c c3 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d bd ba 0c 00 f7 d8 64 89 01 48
[  733.712551] RSP: 002b:00007ffcf95c80e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[  733.712553] RAX: ffffffffffffffda RBX: 00007ffcf95c8120 RCX: 00007f30bb52738b
[  733.712554] RDX: 00007ffcf95c8120 RSI: 00000000c06864a2 RDI: 000000000000000f
[  733.712555] RBP: 00000000c06864a2 R08: 0000000000000000 R09: 00005607e34f2d80
[  733.712556] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[  733.712557] R13: 000000000000000f R14: 00005607e34f2d80 R15: 0000000000000000
[  733.712559] Modules linked in: snd_seq_dummy snd_hrtimer uinput nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 iptable_mangle iptable_raw iptable_security rfkill ip_set nf_tables nfnetlink ip6table_filter ip6_tables iptable_filter sunrpc squashfs loop snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi edac_mce_amd snd_hda_intel snd_intel_dspcfg snd_hda_codec ppdev kvm snd_hda_core snd_hwdep snd_seq snd_seq_device irqbypass snd_pcm rapl snd_timer snd sp5100_tco wmi_bmof pcspkr k10temp i2c_piix4 soundcore parport_pc parport gpio_amdpt gpio_generic acpi_cpufreq zram ip_tables amdgpu iommu_v2 gpu_sched i2c_algo_bit ttm drm_kms_helper crct10dif_pclmul crc32_pclmul crc32c_intel cec ghash_clmulni_intel drm uas ccp usb_storage nvme r8169 nvme_core wmi pinctrl_amd fuse
[  733.712593] ---[ end trace 9264b2e76202f4d0 ]---
[  733.712699] RIP: 0010:dm_update_crtc_state+0x5aa/0x700 [amdgpu]
[  733.712702] Code: c0 bf 02 00 00 00 48 c7 c6 e0 f0 a6 c0 e8 5e 24 d2 ff b8 f4 ff ff ff e9 a1 fb ff ff 4d 85 d2 0f 85 7d fb ff ff e9 91 fb ff ff <0f> 0b 49 8b b3 78 01 00 00 4c 89 d7 e8 d5 9e 12 00 4c 8b 54 24 10
[  733.712703] RSP: 0018:ffffa19588a8bad8 EFLAGS: 00010246
[  733.712704] RAX: ffff8c1ddf9cb001 RBX: ffff8c1ead5ef000 RCX: 0000000000001fd5
[  733.712705] RDX: 0000000000001fd4 RSI: cf33a87491252d49 RDI: 000000000002f180
[  733.712706] RBP: ffff8c1ea9e07000 R08: ffff8c1edf355ef8 R09: ffff8c1edf355ef8
[  733.712707] R10: ffff8c1ddf9ca000 R11: 0000000000000006 R12: ffff8c1eb7fd6c00
[  733.712708] R13: 0000000000000000 R14: 0000000000000001 R15: ffff8c1e3238de00
[  733.712710] FS:  00007f30bafb5a80(0000) GS:ffff8c1ebe9c0000(0000) knlGS:0000000000000000
[  733.712711] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  733.712712] CR2: 00007f3066b6f000 CR3: 0000000721844000 CR4: 0000000000350ee0

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