Hi, I did some exhaustive testing, but first mi current setup: Current base install is 14.04.3 with HWE Vivid, so that's kernel 3.19.0-30. With no extra parameters bootup will still give wrong resolution and monitor is not properly detected, so “unknown”. Bootup with kernel parameter drm_kms_helper.edid_firmware=DP-1:edid/U2415.edid gives consistently correct resolution and monitor is properly detected. Once in a while the U2415 is off when it should be on, but switching back and forth with VT gets the monitor on. So not much changes since last tests.
But testing with the following newer kernels: 4.0.0-040000, 4.0.9-0400090, 4.1.0-040100, 4.1.10-040110, 4.2.3-040203 and 4.3.0-040300rc6 Monitor is properly detected and resolution is correct since 4.1.0-040100. Still correct in 4.3.0-040300rc6. So since 4.1.0-040100 there's no need for me to add the extra edid kernel parameter anymore. So you I guess we can say its fixed in 4.1.0-040100. However since 4.0.0-040000 I got another issue that might be related. After suspend/resume the graphics are sloppy, kind of slow motion feel, mouse and keyboard input have great lag, response very slow. A reboot can solve that, but also disconnecting displayport. And this only happens with displayport connected with U2415. Should I file this in a new bug report? Think I will report these results in the upstream bug report too. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1412730 Title: DELL U2415 monitor detection issue To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1412730/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
