gistfile1.txt

##### 1. river: did the output commit fail? #####
234:(waybar:2162): LIBDBUSMENU-GLIB-WARNING **: 19:04:21.965: Unable to replace properties on 0:info(output): applying output configuration
235:error(output): failed to commit new output configuration
260:info(output): applying output configuration

##### 2. kernel: connector state for eDP-1 #####
/sys/class/drm/card2-eDP-1
  enabled = disabled
  dpms    = Off
  status  = connected

##### 3. backlight #####
apple-panel-bl: brightness=150/509 bl_power=0 (0=on, 4=off)

##### 4. recent kernel messages (drm / dcp / edp / backlight) #####
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: CAHandler.cpp:188: IOMFB load_ca_data: Unrecognized data version 0 (expected 1 or 2)
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: UPPipe.cpp:3767: IOMFB read_pmu_data_sync: pmu ram read error (e00800d8)
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: PPipeDCP_H13P.cpp:14085: IOMFB Int RTBandwidth: program_M3_rt_config: Using Dashboard 23b3d05d8
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: UPTSQManager.cpp:133: IOMFB: clearing M3 reset
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: UPTSQ_Hal_v1.cpp:349: IOMFB: timebase_offset = 4
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: UPTSQManager.cpp:105: IOMFB: switch to normal mode succeeded
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: ock_PCC2DLTM_v1.cpp:910: IOMFBStatus IOMFB::UPBlock_PCC2DLTM_v1::set_mcpu_power(IOMFB::AppleRegisterStream *, bool) Loading M3 Hal
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: M3Hal_v1.cpp:197: IOMFB: load LTM M3 IMem : size 0x8e70
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: M3Hal_v1.cpp:197: IOMFB: load LTM M3 DMem : size 0xedd8
May 25 08:17:36 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: PPipeDCP_H13P.cpp:17179: handle_stage1_enable blm_en 0 ltm_en 1
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: PPipeDCP_H13P.cpp:10490: set_run_mode_safe: deferring: 4 -> 1
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: PPipeDCP_H13P.cpp:10395: virtual IOMFBStatus IOMFB::UPPipeDCP_H13P::ready_for_run_mode_change(IOMFB::AppleRegisterStream *): initiating deferred run mod
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: UPTSQManager.cpp:150: IOMFBStatus IOMFB::UPTSQManager::power_down_M3(IOMFB::AppleRegisterStream *, UPTSQManager::ModeChangeWaiter *): request mode ch
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: UPTSQManager.cpp:162: IOMFBStatus IOMFB::UPTSQManager::power_down_M3(IOMFB::AppleRegisterStream *, UPTSQManager::ModeChangeWaiter *): disabling M3
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: PPipeDCP_H13P.cpp:10468: set_run_mode_safe: no need to defer: 1 -> 0
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: eoInterfaceIOAV.cpp:433: IOMFB: VideoInterfaceIOAV::did_power_off: m_power_ctrl->setPower( 0 )
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: eoInterfaceIOAV.cpp:146: IOMFB: IOAVVideoInterface terminated
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: oInterfaceIOAV.cpp:1094: void VideoInterfaceIOAV::unplug_gated(IOAVVideoInterface *): display HPD removed
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: RTKit: syslog message: nifiedPipeline.cpp:1356: set_device_enabled_gated: current state: 1, requested state: 0
May 25 09:13:46 balaam kernel: apple-dcp 231c00000.dcp: dcp_poweroff() done

##### verdict #####
River's output commit FAILED -> this is issue #1471's failure mode.
Next step: echo 0x1ff | sudo tee /sys/module/drm/parameters/debug,
reproduce, capture dmesg, attach to the issue.