Use git to bisect between the current problematic kernel and the last working kernel. Bisecting is a git feature that allows you to bisect the commits between two points to determine what change caused the regression. Google for "git bisect howto". Alex From: Tom Reddish [mailto:tom.reddish@xxxxxxxxxxxxxxxxxxx] Sent: Wednesday, May 31, 2017 12:44 PM To: Deucher, Alexander Cc: Koenig, Christian; amd-gfx at lists.freedesktop.org; Brian Kane Subject: Re: Linux Kernel 4.4.0-66 Possible DRM connector_status Bug For LG Displays What do you mean by bisect? My gut is telling me it's something that changed in the kernel. Maybe the kernel is correctly parsing the information it is being given from the display now and in the older kernel it was handling that information differently? With the exact same display and no settings changed on it if I use the older kernel it shows up as connected Tom Reddish Software Engineer MediaVue Systems Skype: t.reddish Tel: +1 781.926.0676 w<www.mediavuesystems.com>ww.mediavuesystems.com<www.mediavuesystems.com> On May 31, 2017, at 12:24 PM, Deucher, Alexander <Alexander.Deucher at amd.com<mailto:Alexander.Deucher at amd.com>> wrote: Can you bisect? Sounds like the monitor does not keep the EDID powered up when the display is off as is required by the vesa spec. Alex From: Tom Reddish [mailto:tom.reddish@xxxxxxxxxxxxxxxxxxx] Sent: Wednesday, May 31, 2017 12:20 PM To: Deucher, Alexander; Koenig, Christian Cc: amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>; Brian Kane Subject: Linux Kernel 4.4.0-66 Possible DRM connector_status Bug For LG Displays LG Displays are being reported as "disconnected" when they are powered off (currently connected through DVI to mini-displayport adapter) Only seeing this with LG displays (have tested NEC and Samsung *limited model types for each manufacturer*). With the LG display connected to the graphics card and powered off the system is reporting the DisplayPort as disconnected. In any kernel <= 4.4.0-31 the system would report the DisplayPort as connected even if the LG display was off. Kernel tested on Linux version 4.4.0-66-generic (buildd at lgw01-28) (gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.4) ) #87-Ubuntu Most recent kernel without the bug: Linux version 4.4.0-31-generic (buildd at lgw01-16) (gcc version 5.3.1 20160413 (Ubuntu 5.3.1-14ubuntu2.1) ) #50-Ubuntu "cat /sys/class/drm/card1-DP-1/status" will show the status as disconnected if the LG display is powered off Environment Ubuntu 16.04 Graphics Card: Cape Verde PRO [Radeon HD 7750/8740 / R7 250E] Radeon Graphics Drivers Kernel: 4.4.0-66 Processor processor : 0-3 vendor_id : AuthenticAMD cpu family : 21 model : 48 model name : AMD A8-7600 Radeon R7, 10 Compute Cores 4C+6G stepping : 1 microcode : 0x6003106 cpu MHz : 1400.000 cache size : 2048 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 2 apicid : 16 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc extd_apicid aperfmperf eagerfpu pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 popcnt aes xsave avx f16c lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs xop skinit wdt lwp fma4 tce nodeid_msr tbm topoext perfctr_core perfctr_nb bpext cpb hw_pstate vmmcall fsgsbase bmi1 xsaveopt arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold bugs : fxsave_leak sysret_ss_attrs bogomips : 6188.48 TLB size : 1536 4K pages clflush size : 64 cache_alignment : 64 address sizes : 48 bits physical, 48 bits virtual power management: ts ttp tm 100mhzsteps hwpstate cpb eff_freq_ro [13] Loaded driver and hardware information cat /proc/ioports: 0000-03af : PCI Bus 0000:00 0000-001f : dma1 0020-0021 : pic1 0040-0043 : timer0 0050-0053 : timer1 0060-0060 : keyboard 0061-0061 : PNP0800:00 0064-0064 : keyboard 0070-0071 : rtc0 0080-008f : dma page reg 00a0-00a1 : pic2 00c0-00df : dma2 00f0-00ff : PNP0C04:00 00f0-00ff : fpu 03b0-03df : PCI Bus 0000:00 03c0-03df : vesafb 03e0-0cf7 : PCI Bus 0000:00 03f8-03ff : serial 040b-040b : pnp 00:08 04d0-04d1 : pnp 00:07 04d0-04d1 : pnp 00:08 04d6-04d6 : pnp 00:08 0800-0803 : ACPI PM1a_EVT_BLK 0804-0805 : ACPI PM1a_CNT_BLK 0808-080b : ACPI PM_TMR 0810-0815 : ACPI CPU throttle 0820-0827 : ACPI GPE0_BLK 0900-090f : pnp 00:08 0910-091f : pnp 00:08 0a00-0a0f : pnp 00:03 0a00-0a07 : f71882fg 0a10-0a1f : pnp 00:03 0b00-0b07 : piix4_smbus 0b20-0b3f : pnp 00:08 0b20-0b27 : piix4_smbus 0c00-0c01 : pnp 00:08 0c14-0c14 : pnp 00:08 0c50-0c51 : pnp 00:08 0c52-0c52 : pnp 00:08 0c6c-0c6c : pnp 00:08 0c6f-0c6f : pnp 00:08 0cd0-0cd1 : pnp 00:08 0cd2-0cd3 : pnp 00:08 0cd4-0cd5 : pnp 00:08 0cd6-0cd7 : pnp 00:08 0cd8-0cdf : pnp 00:08 0cf8-0cff : PCI conf1 0d00-ffff : PCI Bus 0000:00 d000-dfff : PCI Bus 0000:02 d000-d0ff : 0000:02:00.0 d000-d0ff : r8169 e000-efff : PCI Bus 0000:01 e000-e0ff : 0000:01:00.0 f000-f0ff : 0000:00:01.0 f100-f10f : 0000:00:11.0 f100-f10f : ahci f110-f113 : 0000:00:11.0 f110-f113 : ahci f120-f127 : 0000:00:11.0 f120-f127 : ahci f130-f133 : 0000:00:11.0 f130-f133 : ahci f140-f147 : 0000:00:11.0 f140-f147 : ahci fe00-fefe : pnp 00:08 PCI Information 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Cape Verde PRO [Radeon HD 7750/8740 / R7 250E] (prog-if 00 [VGA controller]) Subsystem: Hightech Information System Ltd. Cape Verde PRO [Radeon HD 7750/8740 / R7 250E] Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+ Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 0, Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 48 Region 0: Memory at c0000000 (64-bit, prefetchable) [size=256M] Region 2: Memory at fea00000 (64-bit, non-prefetchable) [size=256K] Region 4: I/O ports at e000 [size=256] Expansion ROM at fea40000 [disabled] [size=128K] Capabilities: [48] Vendor Specific Information: Len=08 <?> Capabilities: [50] Power Management version 3 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1+,D2+,D3hot+,D3cold-) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- Capabilities: [58] Express (v2) Legacy Endpoint, MSI 00 DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s <4us, L1 unlimited ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset- DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported- RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+ MaxPayload 256 bytes, MaxReadReq 512 bytes DevSta: CorrErr+ UncorrErr- FatalErr- UnsuppReq+ AuxPwr- TransPend- LnkCap: Port #0, Speed 8GT/s, Width x16, ASPM L0s L1, Exit Latency L0s <64ns, L1 <1us ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+ LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+ ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt- LnkSta: Speed 8GT/s, Width x16, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR-, OBFF Not Supported DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis- Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS- Compliance De-emphasis: -6dB LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete+, EqualizationPhase1+ EqualizationPhase2+, EqualizationPhase3+, LinkEqualizationRequest- Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+ Address: 00000000fee00000 Data: 0000 Capabilities: [100 v1] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?> Capabilities: [150 v2] Advanced Error Reporting UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol- UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol- CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+ CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+ AERCap: First Error Pointer: 00, GenCap+ CGenEn- ChkCap+ ChkEn- Capabilities: [200 v1] #15 Capabilities: [270 v1] #19 Kernel driver in use: radeon Kernel modules: radeon Tom Reddish Software Engineer MediaVue Systems Skype: t.reddish Tel: +1 781.926.0676 w<x-msg://8/www.mediavuesystems.com>ww.mediavuesystems.com<x-msg://8/www.mediavuesystems.com> -------------- next part -------------- An HTML attachment was scrubbed... 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