I didn't have a DisplayPort cable before. I used an analog VGA cable and hotplug detection worked reliably.
I could boot a 12.04 LTS LiveCD and test it, if it's important. I'd like to help debug this. It would help if I knew how hotplug detection is supposed to work, and what tools there are for me to see where it gets lost. Does the Intel video kernel driver do the detection? Does it poll or wait for an interrupt? How does the kernel communicate hotplug events to userspace? What tool do I run to watch for those events? -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/1263681 Title: 8086:0126 [Lenovo a ThinkPad X220] DisplayPort-2-DVI not hotplugging Status in “xorg” package in Ubuntu: Incomplete Bug description: WIth my Lenovo ThinkPad X220 I am unable to hotplug a DisplayPort-2-DVI cable, plug the DVI end into a monitor (Samsung SyncMaster 193p+), and plug the DP end into the ThinkPad, and it is detected within a reasonable time, with GNOME automatically extending my desktop. If I *unplug* the DP cable, the unplug is detected instantly. I once waited ~5 minutes without running xrandr, and it actually detected the monitor and reconfigured. WORKAROUND: If I run 'xrandr' in an xterm, the monitor is detected instantly and GNOME reconfigures the screen. WORKAROUND: if I open System Preferences -> Display, it does an xrandr probe and instantly detects/reconfigures the screen. WORKAROUND: if I plug the DP cable before I open the laptop lid to wake it up from S3 sleep, the external monitor is detected. WORKAROUND: if I use a VGA cable instead of the DP -> DVI one, hotplug is detected within seconds. ProblemType: Bug DistroRelease: Ubuntu 13.10 Package: linux-image-extra-3.11.0-15-generic 3.11.0-15.23 ProcVersionSignature: Ubuntu 3.11.0-15.23-generic 3.11.10 Uname: Linux 3.11.0-15-generic x86_64 ApportVersion: 2.12.5-0ubuntu2.2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: mg 2722 F.... pulseaudio Date: Mon Dec 23 14:33:12 2013 EcryptfsInUse: Yes HibernationDevice: RESUME=UUID=bf592a79-5f4e-486d-b69d-7525d492dcc6 InstallationDate: Installed on 2012-07-25 (515 days ago) InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425) Lsusb: Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: LENOVO 4291WJF MarkForUpload: True ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-15-generic root=UUID=36079681-53fc-4ca2-80ac-98321c07e8d2 ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.11.0-15-generic N/A linux-backports-modules-3.11.0-15-generic N/A linux-firmware 1.116 RfKill: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no SourcePackage: linux UpgradeStatus: Upgraded to saucy on 2013-10-17 (66 days ago) WifiSyslog: dmi.bios.date: 05/31/2011 dmi.bios.vendor: LENOVO dmi.bios.version: 8DET47WW (1.17 ) dmi.board.asset.tag: Not Available dmi.board.name: 4291WJF dmi.board.vendor: LENOVO dmi.board.version: Not Available dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Not Available dmi.modalias: dmi:bvnLENOVO:bvr8DET47WW(1.17):bd05/31/2011:svnLENOVO:pn4291WJF:pvrThinkPadX220:rvnLENOVO:rn4291WJF:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable: dmi.product.name: 4291WJF dmi.product.version: ThinkPad X220 dmi.sys.vendor: LENOVO --- ApportVersion: 2.12.7-0ubuntu6 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: ubuntu 2713 F.... pulseaudio CasperVersion: 1.336ubuntu1 CurrentDesktop: Unity DistroRelease: Ubuntu 14.04 LiveMediaBuild: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64 (20140109) Lsusb: Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 003: ID 090c:1000 Silicon Motion, Inc. - Taiwan (formerly Feiya Technology Corp.) Flash Drive Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: LENOVO 4291WJF MarkForUpload: True Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: file=/cdrom/preseed/username.seed boot=casper initrd=/casper/initrd.lz quiet splash -- maybe-ubiquity ProcVersionSignature: Ubuntu 3.13.0-1.16-generic 3.13.0-rc7 RelatedPackageVersions: linux-restricted-modules-3.13.0-1-generic N/A linux-backports-modules-3.13.0-1-generic N/A linux-firmware 1.119 RfKill: 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no Tags: trusty Uname: Linux 3.13.0-1-generic x86_64 UpgradeStatus: No upgrade log present (probably fresh install) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo dmi.bios.date: 07/18/2013 dmi.bios.vendor: LENOVO dmi.bios.version: 8DET69WW (1.39 ) dmi.board.asset.tag: Not Available dmi.board.name: 4291WJF dmi.board.vendor: LENOVO dmi.board.version: Not Available dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Not Available dmi.modalias: dmi:bvnLENOVO:bvr8DET69WW(1.39):bd07/18/2013:svnLENOVO:pn4291WJF:pvrThinkPadX220:rvnLENOVO:rn4291WJF:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable: dmi.product.name: 4291WJF dmi.product.version: ThinkPad X220 dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1263681/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
