[BUG,BISECTED] WARNING dcn20_find_secondary_pipe

[Chris Bainbridge <chris.bainbridge@gmail.com>]

Hardware is HP Pavilion Aero 13 laptop with Dell WD19 dock and three
external monitors. I get a warning with recent kernel builds when
enabling the external monitors with xrandr after initial boot:

16:57:49 kernel: WARNING: CPU: 4 PID: 1347 at drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn20/dcn20_resource.c:1734 dcn20_find_secondary_pipe+0x1a6/0x400 [amdgpu]
16:57:49 kernel: Modules linked in: rfcomm xt_conntrack nft_chain_nat xt_MASQUERADE nf_nat nf_conntrack_netlink nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 xfrm_user xfrm_algo xt_addrtype nft_compat nf_tables nfnetlink br_netfilter bridge stp llc nvme_fabrics ccm snd_seq_dummy snd_hrtimer snd_seq cmac algif_hash algif_skcipher af_alg bnep qrtr overlay binfmt_misc snd_acp3x_pdm_dma snd_soc_dmic snd_acp3x_rn snd_sof_amd_rembrandt snd_sof_amd_renoir snd_sof_amd_acp snd_sof_pci snd_sof_xtensa_dsp snd_sof snd_sof_utils snd_ctl_led snd_soc_core snd_hda_codec_realtek snd_compress snd_hda_codec_generic snd_pci_ps snd_hda_scodec_component snd_soc_acpi_amd_match snd_hda_codec_hdmi snd_rpl_pci_acp6x uvcvideo snd_hda_intel snd_usb_audio snd_acp_pci iwlmvm videobuf2_vmalloc btusb snd_intel_dspcfg intel_rapl_msr snd_usbmidi_lib snd_acp_legacy_common videobuf2_memops btrtl intel_rapl_common snd_pci_acp6x snd_hda_codec snd_ump uvc mac80211 btintel snd_pci_acp5x snd_hwdep kvm_amd videobuf2_v4l2 snd_rawmidi btbcm libarc4 snd_hda_core
16:57:49 kernel:  snd_seq_device snd_rn_pci_acp3x btmtk videodev kvm hp_wmi snd_pcm snd_acp_config ucsi_acpi iwlwifi ee1004 videobuf2_common platform_profile rapl snd_timer snd_soc_acpi pcspkr sparse_keymap bluetooth typec_ucsi wmi_bmof k10temp sp5100_tco snd_pci_acp3x snd ccp mc cfg80211 soundcore typec input_leds joydev amd_pmc acpi_tad serio_raw mac_hid msr parport_pc ppdev lp parport efi_pstore dmi_sysfs ip_tables x_tables autofs4 btrfs blake2b_generic xor raid6_pq dm_crypt hid_microsoft ff_memless usbmouse usbkbd hid_cmedia r8153_ecm cdc_ether usbnet usbhid r8152 mii amdgpu i2c_algo_bit drm_ttm_helper ttm drm_panel_backlight_quirks drm_exec drm_suballoc_helper uas cec hid_multitouch usb_storage rc_core hid_generic amdxcp polyval_clmulni drm_buddy nvme i2c_hid_acpi polyval_generic gpu_sched i2c_piix4 nvme_core amd_sfh i2c_hid video ghash_clmulni_intel drm_display_helper i2c_smbus nvme_auth hid wmi aesni_intel crypto_simd cryptd
16:57:49 kernel: CPU: 4 UID: 0 PID: 1347 Comm: Xorg Not tainted 6.13.0-07078-gb46c89c08f41 #139
16:57:49 kernel: Hardware name: HP HP Pavilion Aero Laptop 13-be0xxx/8916, BIOS F.16 08/01/2024
16:57:49 kernel: RIP: 0010:dcn20_find_secondary_pipe+0x1a6/0x400 [amdgpu]
16:57:49 kernel: Code: 48 69 db b8 0f 00 00 49 8d 44 1d 00 44 88 a0 24 08 00 00 48 85 c0 75 c7 49 8b 86 98 05 00 00 44 8b a0 a8 02 00 00 41 83 ec 01 <0f> 0b 45 85 e4 78 ac 44 89 e0 48 69 c0 b8 0f 00 00 4d 8d 74 05 08
16:57:49 kernel: RSP: 0018:ffff9efc4383f478 EFLAGS: 00010206
16:57:49 kernel: RAX: ffff910e59a6f800 RBX: 0000000000000000 RCX: ffff910ea4a02218
16:57:49 kernel: RDX: ffff910e59a6f800 RSI: ffff910ea4a002a8 RDI: ffff910e59400000
16:57:49 kernel: RBP: ffff9efc4383f4b0 R08: ffff910ea4a02218 R09: 0000000000000000
16:57:49 kernel: R10: ffff9efc4383f5d0 R11: 0000000000000000 R12: 0000000000000003
16:57:49 kernel: R13: ffff910ea4a002a8 R14: ffff910e59400000 R15: fffffffffffff048
16:57:49 kernel: FS:  0000711c38030ac0(0000) GS:ffff91114e400000(0000) knlGS:0000000000000000
16:57:49 kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
16:57:49 kernel: CR2: 00007cae3d793018 CR3: 000000010d5b1000 CR4: 0000000000f50ef0
16:57:49 kernel: PKRU: 55555554
16:57:49 kernel: Call Trace:
16:57:49 kernel:  <TASK>
16:57:49 kernel:  ? show_regs+0x68/0x80
16:57:49 kernel:  ? __warn+0x93/0x1b0
16:57:49 kernel:  ? dcn20_find_secondary_pipe+0x1a6/0x400 [amdgpu]
16:57:49 kernel:  ? report_bug+0x17e/0x1b0
16:57:49 kernel:  ? handle_bug+0x6a/0xb0
16:57:49 kernel:  ? exc_invalid_op+0x18/0x80
16:57:49 kernel:  ? asm_exc_invalid_op+0x1b/0x20
16:57:49 kernel:  ? dcn20_find_secondary_pipe+0x1a6/0x400 [amdgpu]
16:57:49 kernel:  dcn21_fast_validate_bw+0x409/0x740 [amdgpu]
16:57:49 kernel:  dcn21_validate_bandwidth_fp+0xd6/0xf20 [amdgpu]
16:57:49 kernel:  ? __might_sleep+0x58/0x90
16:57:49 kernel:  dcn21_validate_bandwidth+0x62/0xa0 [amdgpu]
16:57:49 kernel:  ? dcn21_validate_bandwidth+0x62/0xa0 [amdgpu]
16:57:49 kernel:  dc_validate_global_state+0x444/0x600 [amdgpu]
16:57:49 kernel:  ? drm_dp_mst_atomic_check+0xbd/0x100 [drm_display_helper]
16:57:49 kernel:  amdgpu_dm_atomic_check+0x17ae/0x1940 [amdgpu]
16:57:49 kernel:  drm_atomic_check_only+0x6a4/0xb30
16:57:49 kernel:  drm_atomic_commit+0x6f/0xe0
16:57:49 kernel:  ? __drm_printfn_seq_file+0x30/0x30
16:57:49 kernel:  drm_atomic_helper_set_config+0x7e/0xc0
16:57:49 kernel:  drm_mode_setcrtc+0x416/0x9e0
16:57:49 kernel:  ? __lock_acquire+0x415/0x27d0
16:57:49 kernel:  ? __lock_acquire+0x415/0x27d0
16:57:49 kernel:  ? drm_mode_getcrtc+0x1e0/0x1e0
16:57:49 kernel:  drm_ioctl_kernel+0xb5/0x120
16:57:49 kernel:  drm_ioctl+0x300/0x5a0
16:57:49 kernel:  ? drm_mode_getcrtc+0x1e0/0x1e0
16:57:49 kernel:  amdgpu_drm_ioctl+0x4e/0x90 [amdgpu]
16:57:49 kernel:  __x64_sys_ioctl+0xa0/0xd0
16:57:49 kernel:  x64_sys_call+0xee7/0xfb0
16:57:49 kernel:  do_syscall_64+0x87/0x140
16:57:49 kernel:  ? find_held_lock+0x31/0x90
16:57:49 kernel:  ? find_held_lock+0x31/0x90
16:57:49 kernel:  ? lock_release+0xdb/0x2c0
16:57:49 kernel:  ? dput.part.0+0x91/0x460
16:57:49 kernel:  ? dput.part.0+0x9b/0x460
16:57:49 kernel:  ? dput+0x13/0x20
16:57:49 kernel:  ? __fsnotify_parent+0x200/0x3b0
16:57:49 kernel:  ? find_held_lock+0x31/0x90
16:57:49 kernel:  ? find_held_lock+0x31/0x90
16:57:49 kernel:  ? lock_release+0xdb/0x2c0
16:57:49 kernel:  ? __f_unlock_pos+0x15/0x20
16:57:49 kernel:  ? __mutex_unlock_slowpath+0x41/0x2e0
16:57:49 kernel:  ? mutex_unlock+0x12/0x20
16:57:49 kernel:  ? trace_irq_disable+0x7b/0xb0
16:57:49 kernel:  ? trace_irq_enable+0x7b/0xb0
16:57:49 kernel:  ? syscall_exit_to_user_mode+0xcc/0x210
16:57:49 kernel:  ? do_syscall_64+0x93/0x140
16:57:49 kernel:  ? do_syscall_64+0x93/0x140
16:57:49 kernel:  ? sysvec_apic_timer_interrupt+0x57/0xc0
16:57:49 kernel:  entry_SYSCALL_64_after_hwframe+0x4b/0x53
16:57:49 kernel: RIP: 0033:0x711c3831ccdb
16:57:49 kernel: Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
16:57:49 kernel: RSP: 002b:00007fffe26e36f0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
16:57:49 kernel: RAX: ffffffffffffffda RBX: 0000592748268ac0 RCX: 0000711c3831ccdb
16:57:49 kernel: RDX: 00007fffe26e3780 RSI: 00000000c06864a2 RDI: 000000000000000f
16:57:49 kernel: RBP: 00007fffe26e3780 R08: 0000000000000000 R09: 0000000000000000
16:57:49 kernel: R10: 0000000000000000 R11: 0000000000000246 R12: 00000000c06864a2
16:57:49 kernel: R13: 000000000000000f R14: 0000000000000000 R15: 0000000000000000
16:57:49 kernel:  </TASK>
16:57:49 kernel: irq event stamp: 2276151
16:57:49 kernel: hardirqs last  enabled at (2276157): [<ffffffffa985a9c5>] __up_console_sem+0x75/0x90
16:57:49 kernel: hardirqs last disabled at (2276162): [<ffffffffa985a9aa>] __up_console_sem+0x5a/0x90
16:57:49 kernel: softirqs last  enabled at (2274574): [<ffffffffa979ecff>] __irq_exit_rcu+0xbf/0xf0
16:57:49 kernel: softirqs last disabled at (2274567): [<ffffffffa979ecff>] __irq_exit_rcu+0xbf/0xf0
16:57:49 kernel: ---[ end trace 0000000000000000 ]---

The bisect leads to a merge commit 43102a2012c2 ("Merge tag
'drm-misc-fixes-2024-09-26'"). Neither parent commit produces the
warning, but the merged commit does.

There are two commits that interact to cause this warning:

2a2a865aee43 ("drm/amd/display: Add all planes on CRTC to state for
overlay cursor").

and

70a6587dca37 ("drm/dp_mst: Fix DSC decompression detection in Synaptics
branch devices")

2a2a865aee43 was added to the mainline Linux repo first, but the warning
only appears following the merge of 70a6587dca37.

#regzbot introduced: 43102a2012c2