Some error message could be found in dmesg output, but they won't be generated when this happens
** Attachment added: "dmesg.log" https://bugs.launchpad.net/hwe-next/+bug/1407913/+attachment/4292806/+files/dmesg.log -- 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/1407913 Title: In 3840x2160 high resolution mode, display would blink with Chrome / Chromium browser opened, or with certain page in Firefox Status in HWE Next Project: New Status in linux package in Ubuntu: Confirmed Bug description: CID: 201410-15952 Dell Inspiron 7548 I'm not sure which package to blame with, I guess maybe it has something to do with X, thing is: when the system is running in 3840*2160 resolution, the display will blink with these browsers under certain conditions. Steps: 1. Install 14.04.1 + update + Chromium + Chrome 2. Make sure it's running with the highest resolution and open Chrome (39.0.2171.95-1) 3. Make sure it's running with the highest resolution and open Chromium (39.0.2171.65-0ubuntu0.14.04.1.1064) 4. Make sure it's running with the highest resolution and open Firefox (34.0+build2-0ubuntu0.14.04.1) 5. Switch to the second-highest resolution mode and repeat 2-4 Expected result: * Every browser should not intefere the display on this system. Actual result: * On step 2, display blinks right after Chrome opened, back to normal when you close the browser * On step 3, display blinks right after Chromium opened, back to normal when you close the browser * On step 4, it won't blink, but if you visit https://bugzilla.mozilla.org/show_bug.cgi?id=1118140 with 100% zoom scale in Firefox, it will blink. If you zoom in or out with ctrl +/- or close it, the display will back to normal. * On step 5, non of them will make the display blink Note that when it's blinking, you can switch to console with Ctrl + Alt + F1 without any problem. And this happen to Firefox on some other pages as well. Verified with: 3.16.0-28 + open source video driver the latest mainline kernel 3.19.0-rc3 + open source video driver 3.13.0-43 + open source video driver 3.13.0-43 + the latest AMD video driver (14.501.1003) in both power-saving and performance mode they all have the same behaviour. Please find the attachment for screencast from step 2 to 4. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.13.0-43-generic 3.13.0-43.72 ProcVersionSignature: Ubuntu 3.13.0-43.72-generic 3.13.11.11 Uname: Linux 3.13.0-43-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.6 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: ubuntu 1766 F.... pulseaudio /dev/snd/controlC0: ubuntu 1766 F.... pulseaudio CRDA: country TW: (2402 - 2472 @ 40), (3, 27) (5270 - 5330 @ 40), (3, 17), DFS (5735 - 5815 @ 40), (3, 30) CurrentDesktop: Unity Date: Tue Jan 6 03:43:19 2015 HibernationDevice: RESUME=UUID=3121f09d-4ad7-4946-b905-ee8e56a6d914 InstallationDate: Installed on 2015-01-05 (0 days ago) InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2) MachineType: Dell Inc. Inspiron 7548 ProcFB: 0 inteldrmfb 1 radeondrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-43-generic.efi.signed root=UUID=57666a30-96f3-478b-b3c1-3879ce81c53f ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.13.0-43-generic N/A linux-backports-modules-3.13.0-43-generic N/A linux-firmware 1.127.11 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 11/19/2014 dmi.bios.vendor: Dell Inc. dmi.bios.version: A00 dmi.board.name: BBE4C1 dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 8 dmi.chassis.vendor: Dell Inc. dmi.chassis.version: Not Specified dmi.modalias: dmi:bvnDellInc.:bvrA00:bd11/19/2014:svnDellInc.:pnInspiron7548:pvrA00:rvnDellInc.:rnBBE4C1:rvrA00:cvnDellInc.:ct8:cvrNotSpecified: dmi.product.name: Inspiron 7548 dmi.product.version: A00 dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1407913/+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