For the past couple of weeks I've been encountering a weird problem on -current amd64 -- my screen intermittently blanks for around 2-4 seconds when running xorg. At first I thought this was a hardware problem (the machine isn't a spring chicken), but then ffmpeg caught the blanking while I was doing a screencast (i.e. the recording of the xorg part of things goes entirely blank for a couple of seconds), so it seems to be a software problem.
Unfortunately I can't seem to find any obvious trigger. It seems to happen more often when the machine is under heavy load, but sometimes it happens under light load. Frankly, I don't have any real idea *what* could be causing it, and I'm hoping that someone else might have seen this, and perhaps have been equally baffled as to the cause! Laurie OpenBSD 6.8 (GENERIC.MP) #94: Tue Sep 29 00:13:21 MDT 2020 dera...@amd64.openbsd.org:/usr/src/sys/arch/amd64/compile/GENERIC.MP real mem = 17028239360 (16239MB) avail mem = 16497115136 (15732MB) random: good seed from bootblocks mpath0 at root scsibus0 at mpath0: 256 targets mainbus0 at root bios0 at mainbus0: SMBIOS rev. 3.0 @ 0xc3200000 (89 entries) bios0: vendor American Megatrends Inc. version "3805" date 05/16/2018 bios0: ASUSTeK COMPUTER INC. Z170M-PLUS acpi0 at bios0: ACPI 6.1 acpi0: sleep states S0 S3 S4 S5 acpi0: tables DSDT FACP APIC FPDT BGRT MCFG SSDT FIDT SSDT SSDT HPET SSDT SSDT UEFI SSDT LPIT WSMT SSDT SSDT DBGP DBG2 acpi0: wakeup devices PEG0(S4) PEGP(S4) PEG1(S4) PEGP(S4) PEG2(S4) PEGP(S4) SIO1(S3) UAR1(S4) RP09(S4) PXSX(S4) RP10(S4) PXSX(S4) RP11(S4) PXSX(S4) RP12(S4) PXSX(S4) [...] acpitimer0 at acpi0: 3579545 Hz, 24 bits acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat cpu0 at mainbus0: apid 0 (boot processor) cpu0: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz, 4121.53 MHz, 06-5e-03 cpu0: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,HLE,AVX2,SMEP,BMI2,ERMS,INVPCID,RTM,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,MD_CLEAR,TSXFA,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES,MELTDOWN cpu0: 256KB 64b/line 8-way L2 cache cpu0: smt 0, core 0, package 0 mtrr: Pentium Pro MTRR support, 10 var ranges, 88 fixed ranges cpu0: apic clock running at 24MHz cpu0: mwait min=64, max=64, C-substates=0.2.1.2.4.1, IBE cpu1 at mainbus0: apid 2 (application processor) cpu1: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz, 4120.01 MHz, 06-5e-03 cpu1: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,HLE,AVX2,SMEP,BMI2,ERMS,INVPCID,RTM,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,MD_CLEAR,TSXFA,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES,MELTDOWN cpu1: 256KB 64b/line 8-way L2 cache cpu1: smt 0, core 1, package 0 cpu2 at mainbus0: apid 4 (application processor) cpu2: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz, 4120.01 MHz, 06-5e-03 cpu2: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,HLE,AVX2,SMEP,BMI2,ERMS,INVPCID,RTM,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,MD_CLEAR,TSXFA,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES,MELTDOWN cpu2: 256KB 64b/line 8-way L2 cache cpu2: smt 0, core 2, package 0 cpu3 at mainbus0: apid 6 (application processor) cpu3: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz, 4120.01 MHz, 06-5e-03 cpu3: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,EST,TM2,SSSE3,SDBG,FMA3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,MOVBE,POPCNT,DEADLINE,AES,XSAVE,AVX,F16C,RDRAND,NXE,PAGE1GB,RDTSCP,LONG,LAHF,ABM,3DNOWP,PERF,ITSC,FSGSBASE,TSC_ADJUST,SGX,BMI1,HLE,AVX2,SMEP,BMI2,ERMS,INVPCID,RTM,MPX,RDSEED,ADX,SMAP,CLFLUSHOPT,PT,MD_CLEAR,TSXFA,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,XSAVEC,XGETBV1,XSAVES,MELTDOWN cpu3: 256KB 64b/line 8-way L2 cache cpu3: smt 0, core 3, package 0 ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 120 pins acpimcfg0 at acpi0 acpimcfg0: addr 0xf8000000, bus 0-63 acpihpet0 at acpi0: 23999999 Hz acpiprt0 at acpi0: bus 0 (PCI0) acpiprt1 at acpi0: bus -1 (PEG0) acpiprt2 at acpi0: bus -1 (PEG1) acpiprt3 at acpi0: bus -1 (PEG2) acpiprt4 at acpi0: bus 4 (RP09) acpiprt5 at acpi0: bus -1 (RP10) acpiprt6 at acpi0: bus -1 (RP11) acpiprt7 at acpi0: bus -1 (RP12) acpiprt8 at acpi0: bus -1 (RP13) acpiprt9 at acpi0: bus 3 (RP01) acpiprt10 at acpi0: bus -1 (RP02) acpiprt11 at acpi0: bus -1 (RP03) acpiprt12 at acpi0: bus -1 (RP04) acpiprt13 at acpi0: bus -1 (RP05) acpiprt14 at acpi0: bus -1 (RP06) acpiprt15 at acpi0: bus -1 (RP07) acpiprt16 at acpi0: bus -1 (RP08) acpiprt17 at acpi0: bus 1 (RP17) acpiprt18 at acpi0: bus -1 (RP18) acpiprt19 at acpi0: bus -1 (RP19) acpiprt20 at acpi0: bus 2 (RP20) acpiprt21 at acpi0: bus -1 (RP21) acpiprt22 at acpi0: bus -1 (RP22) acpiprt23 at acpi0: bus -1 (RP23) acpiprt24 at acpi0: bus -1 (RP24) acpiprt25 at acpi0: bus -1 (RP14) acpiprt26 at acpi0: bus -1 (RP15) acpiprt27 at acpi0: bus -1 (RP16) acpiec0 at acpi0: not present acpipci0 at acpi0 PCI0: 0x00000004 0x00000011 0x00000001 acpicmos0 at acpi0 "PNP0C14" at acpi0 not configured acpibtn0 at acpi0: SLPB "INT33A1" at acpi0 not configured acpibtn1 at acpi0: PWRB "PNP0C0B" at acpi0 not configured "PNP0C0B" at acpi0 not configured "PNP0C0B" at acpi0 not configured "PNP0C0B" at acpi0 not configured "PNP0C0B" at acpi0 not configured "PNP0C14" at acpi0 not configured acpicpu0 at acpi0: C1(@1 halt!), PSS acpicpu1 at acpi0: C1(@1 halt!), PSS acpicpu2 at acpi0: C1(@1 halt!), PSS acpicpu3 at acpi0: C1(@1 halt!), PSS acpipwrres0 at acpi0: PG00, resource for PEG0 acpipwrres1 at acpi0: PG01, resource for PEG1 acpipwrres2 at acpi0: PG02, resource for PEG2 acpipwrres3 at acpi0: WRST acpipwrres4 at acpi0: WRST acpipwrres5 at acpi0: WRST acpipwrres6 at acpi0: WRST acpipwrres7 at acpi0: WRST acpipwrres8 at acpi0: WRST acpipwrres9 at acpi0: WRST acpipwrres10 at acpi0: WRST acpipwrres11 at acpi0: WRST acpipwrres12 at acpi0: WRST acpipwrres13 at acpi0: WRST acpipwrres14 at acpi0: WRST acpipwrres15 at acpi0: WRST acpipwrres16 at acpi0: WRST acpipwrres17 at acpi0: WRST acpipwrres18 at acpi0: WRST acpipwrres19 at acpi0: WRST acpipwrres20 at acpi0: WRST acpipwrres21 at acpi0: WRST acpipwrres22 at acpi0: WRST acpipwrres23 at acpi0: FN00, resource for FAN0 acpipwrres24 at acpi0: FN01, resource for FAN1 acpipwrres25 at acpi0: FN02, resource for FAN2 acpipwrres26 at acpi0: FN03, resource for FAN3 acpipwrres27 at acpi0: FN04, resource for FAN4 acpitz0 at acpi0: critical temperature is 119 degC acpitz1 at acpi0: critical temperature is 119 degC acpivideo0 at acpi0: GFX0 cpu0: using VERW MDS workaround (except on vmm entry) cpu0: Enhanced SpeedStep 4121 MHz: speeds: 4001, 4000, 3800, 3500, 3300, 3100, 2900, 2600, 2400, 2200, 1900, 1700, 1500, 1300, 1000, 800 MHz pci0 at mainbus0 bus 0 pchb0 at pci0 dev 0 function 0 "Intel Core 6G Host" rev 0x07 inteldrm0 at pci0 dev 2 function 0 "Intel HD Graphics 530" rev 0x06 drm0 at inteldrm0 inteldrm0: msi, SKYLAKE, gen 9 xhci0 at pci0 dev 20 function 0 "Intel 100 Series xHCI" rev 0x31: msi, xHCI 1.0 usb0 at xhci0: USB revision 3.0 uhub0 at usb0 configuration 1 interface 0 "Intel xHCI root hub" rev 3.00/1.00 addr 1 "Intel 100 Series MEI" rev 0x31 at pci0 dev 22 function 0 not configured ahci0 at pci0 dev 23 function 0 "Intel 100 Series AHCI" rev 0x31: msi, AHCI 1.3.1 ahci0: PHY offline on port 0 ahci0: PHY offline on port 1 ahci0: PHY offline on port 2 ahci0: PHY offline on port 3 ahci0: PHY offline on port 4 ahci0: port 5: 1.5Gb/s scsibus1 at ahci0: 32 targets cd0 at scsibus1 targ 5 lun 0: <ATAPI, iHAS124 F, CL98> removable ppb0 at pci0 dev 27 function 0 "Intel 100 Series PCIE" rev 0xf1 pci1 at ppb0 bus 1 ppb1 at pci0 dev 27 function 3 "Intel 100 Series PCIE" rev 0xf1: msi pci2 at ppb1 bus 2 iwm0 at pci2 dev 0 function 0 "Intel Dual Band Wireless AC 7260" rev 0x73, msi ppb2 at pci0 dev 28 function 0 "Intel 100 Series PCIE" rev 0xf1 pci3 at ppb2 bus 3 ppb3 at pci0 dev 29 function 0 "Intel 100 Series PCIE" rev 0xf1: msi pci4 at ppb3 bus 4 nvme0 at pci4 dev 0 function 0 "ADATA Technology SX8200 Pro" rev 0x03: msix, NVMe 1.3 nvme0: ADATA SX8200PNP, firmware 32B2T6TA, serial 2K31291244PH scsibus2 at nvme0: 2 targets, initiator 0 sd0 at scsibus2 targ 1 lun 0: <NVMe, ADATA SX8200PNP, 32B2> sd0: 976762MB, 512 bytes/sector, 2000409264 sectors pcib0 at pci0 dev 31 function 0 "Intel Z170 LPC" rev 0x31 "Intel 100 Series PMC" rev 0x31 at pci0 dev 31 function 2 not configured azalia0 at pci0 dev 31 function 3 "Intel 100 Series HD Audio" rev 0x31: msi azalia0: codecs: Realtek/0x0887, Intel/0x2809, using Realtek/0x0887 audio0 at azalia0 ichiic0 at pci0 dev 31 function 4 "Intel 100 Series SMBus" rev 0x31: apic 2 int 16 iic0 at ichiic0 iic0: addr 0x20 01=2a 02=2a 03=13 04=11 05=13 06=e0 07=0a 08=0a 09=0a 0a=0a 0b=22 0c=22 0d=dd 0e=dd 0f=44 10=44 13=73 15=ab 16=2d 17=d5 19=8a 1a=50 1b=68 1c=22 1d=3f 1e=3c 20=70 21=70 22=45 23=44 29=24 2a=3e 2b=fc 2c=fc 2d=22 2e=dd 2f=44 31=73 33=ab 37=8a 38=50 39=3f 3a=3c 3b=45 3c=44 43=3e 44=39 48=03 92=0b b2=29 words 00=00ff 01=2aff 02=2aff 03=13ff 04=11ff 05=13ff 06=e0ff 07=0aff spdmem0 at iic0 addr 0x51: 8GB DDR4 SDRAM PC4-17000 spdmem1 at iic0 addr 0x53: 8GB DDR4 SDRAM PC4-17000 em0 at pci0 dev 31 function 6 "Intel I219-V" rev 0x31: msi, address em0 isa0 at pcib0 isadma0 at isa0 com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo pckbc0 at isa0 port 0x60/5 irq 1 irq 12 pckbd0 at pckbc0 (kbd slot) wskbd0 at pckbd0: console keyboard pcppi0 at isa0 port 0x61 spkr0 at pcppi0 vmm0 at mainbus0: VMX/EPT efifb at mainbus0 not configured uhub1 at uhub0 port 1 configuration 1 interface 0 "VIA Labs, Inc. USB2.0 Hub" rev 2.10/7.04 addr 2 uvideo0 at uhub1 port 2 configuration 1 interface 0 "Logitech HD Pro Webcam C920" rev 2.00/0.19 addr 3 video0 at uvideo0 uaudio0 at uhub1 port 2 configuration 1 interface 3 "Logitech HD Pro Webcam C920" rev 2.00/0.19 addr 3 uaudio0: class v1, high-speed, sync, channels: 0 play, 2 rec, 2 ctls audio1 at uaudio0 uaudio1 at uhub1 port 3 configuration 1 interface 1 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 4 uaudio1: class v2, high-speed, sync, channels: 4 play, 2 rec, 0 ctls audio2 at uaudio1 umidi0 at uhub1 port 3 configuration 1 interface 4 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 4 umidi0: (genuine USB-MIDI) umidi0: out=1, in=1 midi0 at umidi0: <USB MIDI I/F> ugen0 at uhub1 port 3 configuration 1 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 4 uhidev0 at uhub0 port 10 configuration 1 interface 0 "MALTRON USB Multimedia Keyboard" rev 1.10/1.22 addr 5 uhidev0: iclass 3/1 ukbd0 at uhidev0: 8 variable keys, 6 key codes, country code 13 wskbd1 at ukbd0 mux 1 uhidev1 at uhub0 port 10 configuration 1 interface 1 "MALTRON USB Multimedia Keyboard" rev 1.10/1.22 addr 5 uhidev1: iclass 3/0, 3 report ids uhid0 at uhidev1 reportid 2: input=1, output=0, feature=0 uhid1 at uhidev1 reportid 3: input=2, output=0, feature=0 uhidev2 at uhub0 port 14 configuration 1 interface 0 "Logitech USB Receiver" rev 2.00/12.03 addr 6 uhidev2: iclass 3/1 ukbd1 at uhidev2: 8 variable keys, 6 key codes wskbd2 at ukbd1 mux 1 uhidev3 at uhub0 port 14 configuration 1 interface 1 "Logitech USB Receiver" rev 2.00/12.03 addr 6 uhidev3: iclass 3/1, 8 report ids ums0 at uhidev3 reportid 2: 16 buttons, Z and W dir wsmouse0 at ums0 mux 0 uhid2 at uhidev3 reportid 3: input=4, output=0, feature=0 uhid3 at uhidev3 reportid 4: input=1, output=0, feature=0 uhid4 at uhidev3 reportid 8: input=1, output=0, feature=0 uhidev4 at uhub0 port 14 configuration 1 interface 2 "Logitech USB Receiver" rev 2.00/12.03 addr 6 uhidev4: iclass 3/0, 33 report ids uhid5 at uhidev4 reportid 16: input=6, output=6, feature=0 uhid6 at uhidev4 reportid 17: input=19, output=19, feature=0 uhid7 at uhidev4 reportid 32: input=14, output=14, feature=0 uhid8 at uhidev4 reportid 33: input=31, output=31, feature=0 uhub2 at uhub0 port 17 configuration 1 interface 0 "VIA Labs, Inc. USB3.0 Hub" rev 3.20/7.04 addr 7 vscsi0 at root scsibus3 at vscsi0: 256 targets softraid0 at root scsibus4 at softraid0: 256 targets sd1 at scsibus4 targ 1 lun 0: <OPENBSD, SR CRYPTO, 006> sd1: 976761MB, 512 bytes/sector, 2000407649 sectors root on sd1a (9edc4b979e6dd93d.a) swap on sd1b dump on sd1b drm:pid0:skl_ddi_pll_enable *ERROR* [drm] *ERROR* DPLL 1 not locked inteldrm0: 1920x1200, 32bpp wsdisplay0 at inteldrm0 mux 1: console (std, vt100 emulation), using wskbd0 wskbd1: connecting to wsdisplay0 wskbd2: connecting to wsdisplay0 wsdisplay0: screen 1-5 added (std, vt100 emulation) iwm0: hw rev 0x140, fw ver 17.3216344376.0, address XXX drm:pid53467:intel_pipe_update_start *ERROR* [drm] *ERROR* Potential atomic update failure on pipe A video0 detached uvideo0 detached audio1 detached uaudio0 detached audio2 detached uaudio1 detached midi0 detached umidi0 detached ugen0 detached uhub2 detached uhub1 detached uvideo0 at uhub0 port 2 configuration 1 interface 0 "Logitech HD Pro Webcam C920" rev 2.00/0.19 addr 2 video0 at uvideo0 uaudio0 at uhub0 port 2 configuration 1 interface 3 "Logitech HD Pro Webcam C920" rev 2.00/0.19 addr 2 uaudio0: class v1, high-speed, sync, channels: 0 play, 2 rec, 2 ctls audio1 at uaudio0 uaudio1 at uhub0 port 1 configuration 1 interface 1 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 3 uaudio1: class v2, high-speed, sync, channels: 4 play, 2 rec, 0 ctls audio2 at uaudio1 umidi0 at uhub0 port 1 configuration 1 interface 4 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 3 umidi0: (genuine USB-MIDI) umidi0: out=1, in=1 midi0 at umidi0: <USB MIDI I/F> ugen0 at uhub0 port 1 configuration 1 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 3 audio2 detached uaudio1 detached midi0 detached umidi0 detached ugen0 detached uaudio1 at uhub0 port 1 configuration 1 interface 1 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 3 uaudio1: class v2, high-speed, sync, channels: 4 play, 2 rec, 0 ctls audio2 at uaudio1 umidi0 at uhub0 port 1 configuration 1 interface 4 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 3 umidi0: (genuine USB-MIDI) umidi0: out=1, in=1 midi0 at umidi0: <USB MIDI I/F> ugen0 at uhub0 port 1 configuration 1 "Solid State Logic SSL 2+" rev 2.00/0.61 addr 3 uaudio1: play xfer, err = 6 uaudio1: rec xfer, err = 6 drm:pid53467:intel_pipe_update_start *ERROR* [drm] *ERROR* Potential atomic update failure on pipe A