Taihsiang Ho, thank you for reporting this and helping make Ubuntu better. As per http://www.dell.com/support/home/us/en/19/product- support/product/latitude-e7240-ultrabook/drivers/advanced an update to your computer's buggy and outdated BIOS is available (A17). If you update to this following https://help.ubuntu.com/community/BIOSUpdate does it change anything?
Once the BIOS is updated, if the problem is still reproducible: 1) Please provide the output of the following terminal command: sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date 2) Please make a comment specifically advising on if there was an improvement or not. 3) Please mark this report Status Confirmed. If it's not reproducible, please mark this as Invalid. Thank you for your understanding. ** Tags added: bios-outdated-a17 ** Package changed: linux-lts-trusty (Ubuntu) => linux (Ubuntu) ** Changed in: linux (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-lts-trusty in Ubuntu. https://bugs.launchpad.net/bugs/1367671 Title: [Dell Latitude E7240] mini-displayport audio only works via cold-plug or resume from suspend Status in linux package in Ubuntu: Incomplete Bug description: Dell Latitude E7240 (CID 201304-13407) on ubuntu 12.04.5 Steps to reproduce this bug: 1. plug in the mini display port to an external monitor with speaks. 2. click the sound indicator on the unity desktop to choose the correct audio source and test the audio Expected result: there should be displayport audio source ready for you to select. Actual result: No such audio source More information: 1. the audio source could pop up if you cold boot or suspend-resume. 2. HDMI audio of this system could work as hot plug. -------------- ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: linux-image-3.13.0-32-generic 3.13.0-32.57~precise1 [modified: boot/vmlinuz-3.13.0-32-generic] ProcVersionSignature: Ubuntu 3.13.0-32.57~precise1-generic 3.13.11.4 Uname: Linux 3.13.0-32-generic x86_64 AlsaVersion: Advanced Linux Sound Architecture Driver Version k3.13.0-32-generic. ApportVersion: 2.0.1-0ubuntu17.7 Architecture: amd64 ArecordDevices: **** List of CAPTURE Hardware Devices **** card 1: PCH [HDA Intel PCH], device 0: ALC292 Analog [ALC292 Analog] Subdevices: 1/1 Subdevice #0: subdevice #0 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: ubuntu 1726 F.... pulseaudio /dev/snd/controlC0: ubuntu 1726 F.... pulseaudio CRDA: Error: [Errno 2] No such file or directory Card0.Amixer.info: Card hw:0 'HDMI'/'HDA Intel HDMI at 0xf7e34000 irq 64' Mixer name : 'Intel Haswell HDMI' Components : 'HDA:80862807,80860101,00100000' Controls : 21 Simple ctrls : 3 Card1.Amixer.info: Card hw:1 'PCH'/'HDA Intel PCH at 0xf7e30000 irq 65' Mixer name : 'Realtek ALC292' Components : 'HDA:10ec0292,102805ca,00100001' Controls : 28 Simple ctrls : 13 Date: Wed Sep 10 05:43:00 2014 HibernationDevice: RESUME=UUID=12a1f163-a692-48a5-ad30-3bb81ec765d7 InstallationMedia: Ubuntu 12.04.5 LTS "Precise Pangolin" - Release amd64 (20140807.1) MachineType: Dell Inc. Latitude E7240 MarkForUpload: True ProcEnviron: TERM=xterm PATH=(custom, no user) LANG=en_US.UTF-8 SHELL=/bin/bash ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-32-generic root=UUID=357c487a-9f05-4648-995c-b870064d383c ro quiet splash initcall_debug vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.13.0-32-generic N/A linux-backports-modules-3.13.0-32-generic N/A linux-firmware 1.79.16 SourcePackage: linux-lts-trusty UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 10/05/2013 dmi.bios.vendor: Dell Inc. dmi.bios.version: A05 dmi.board.name: 0G05MN dmi.board.vendor: Dell Inc. dmi.board.version: X01 dmi.chassis.type: 9 dmi.chassis.vendor: Dell Inc. dmi.modalias: dmi:bvnDellInc.:bvrA05:bd10/05/2013:svnDellInc.:pnLatitudeE7240:pvr01:rvnDellInc.:rn0G05MN:rvrX01:cvnDellInc.:ct9:cvr: dmi.product.name: Latitude E7240 dmi.product.version: 01 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1367671/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp