I can also confirm that it works more reliable with 3.12.0-031200rc6-generic (and 3.12.0-031200-generic), but it is still not perfect. I would have to ability to test it on two cases where it does not work. Both are beamers (different models, I have to check which one exactly) and both are connected over very long VGA cables. This is still an annoying bug, at least there was some progress so that it started to work again for most monitors I tried. Now it would be nice to get it working on beamers too.
Can I do something to test this? I have checked the dmesg messages and there are no messages like "[drm:intel_dp_i2c_aux_ch] *ERROR* too many retries, giving up" what happened before kernel 3.12 (and maybe kernel 3.11.4). From xrandr output I noticed, that the DP1 connector is shown as disconnected and also no modes are shown (before kernel 3.12 there was sometimes a resolution of the external monitor detected). -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1165965 Title: External display stopped working Status in “linux” package in Ubuntu: Confirmed Bug description: After upgrading to 13.04 beta, my external monitor is no longer detected/driven. This works perfectly under 12.10, and is therefore a major regression impacting common use cases. When the Display Port/VGA adapter is plugged in dmesg reports 15 instances of: [drm:intel_dp_i2c_aux_ch] *ERROR* too many retries, giving up Hardware: MacBook Air 2012 Display configuration: Apple Display Port to VGA adaptor Ubuntu version: 13.04 beta. --- ApportVersion: 2.9.2-0ubuntu5 Architecture: amd64 DistroRelease: Ubuntu 13.04 EcryptfsInUse: Yes InstallationDate: Installed on 2012-07-24 (258 days ago) InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425) MarkForUpload: True Package: linux (not installed) Tags: raring Uname: Linux 3.9.0-030900rc6-generic x86_64 UnreportableReason: The running kernel is not an Ubuntu kernel UpgradeStatus: Upgraded to raring on 2013-04-07 (2 days ago) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo --- ApportVersion: 2.12.5-0ubuntu2 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: mwp 3892 F.... pulseaudio DistroRelease: Ubuntu 13.10 EcryptfsInUse: Yes InstallationDate: Installed on 2012-07-24 (453 days ago) InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425) MachineType: Apple Inc. MacBookAir5,2 MarkForUpload: True NonfreeKernelModules: wl Package: linux (not installed) ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.11.0-12-generic root=UUID=6556813f-c877-4988-bde5-24ac4ec74444 ro nointremap quiet splash i915.i915_enable_rc6=1 vt.handoff=7 ProcVersionSignature: Ubuntu 3.11.0-12.19-generic 3.11.3 RelatedPackageVersions: linux-restricted-modules-3.11.0-12-generic N/A linux-backports-modules-3.11.0-12-generic N/A linux-firmware 1.116 Tags: saucy Uname: Linux 3.11.0-12-generic x86_64 UpgradeStatus: Upgraded to saucy on 2013-10-21 (0 days ago) UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo dmi.bios.date: 05/22/2012 dmi.bios.vendor: Apple Inc. dmi.bios.version: MBA51.88Z.00EF.B00.1205221442 dmi.board.asset.tag: Base Board Asset Tag# dmi.board.name: Mac-2E6FAB96566FE58C dmi.board.vendor: Apple Inc. dmi.board.version: MacBookAir5,2 dmi.chassis.type: 10 dmi.chassis.vendor: Apple Inc. dmi.chassis.version: Mac-2E6FAB96566FE58C dmi.modalias: dmi:bvnAppleInc.:bvrMBA51.88Z.00EF.B00.1205221442:bd05/22/2012:svnAppleInc.:pnMacBookAir5,2:pvr1.0:rvnAppleInc.:rnMac-2E6FAB96566FE58C:rvrMacBookAir5,2:cvnAppleInc.:ct10:cvrMac-2E6FAB96566FE58C: dmi.product.name: MacBookAir5,2 dmi.product.version: 1.0 dmi.sys.vendor: Apple Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1165965/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
