At the risk of posting this in the wrong place ... I encountered a crash just like this today and I believe it's the same thing. I've got a Dell Precision 7530 with a discrete AMD card in bypass/direct mode (the Intel graphics are bypassed).
1. Like the original report, I connected a display to the HDMI output of the laptop 2. I waited several seconds and the external display was not automatically enabled 3. I pressed Win-P to get to the display quick change dialog 4. X crashes to a login screen It's not clear whether the crash was in progress before or after I pressed Win-P. The symptom seems to be the same. The X log shows a bunch of EDID data being read from the HDMI device, then "randr: falling back to unsynchronized pixmap sharing", which is the last message in the crashed X log. Packages on this machine: xserver-common: 2:1.19.6-1ubuntu4.2 xserver-xorg-video-amdgpu-hwe-18.04: 18.1.0-1~18.04.1 Are there any additional data collection steps I can take to confirm that this is the same error or help debug it? -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to xorg-server in Ubuntu. https://bugs.launchpad.net/bugs/1789913 Title: X crashes with "randr: falling back to unsynchronized pixmap sharing" when connecting to an external monitor via HDMI (I+A) Status in xorg-server package in Ubuntu: Fix Released Status in xorg-server-hwe-16.04 package in Ubuntu: Invalid Status in xorg-server source package in Xenial: Won't Fix Status in xorg-server-hwe-16.04 source package in Xenial: Fix Released Status in xorg-server source package in Bionic: Fix Released Status in xorg-server-hwe-16.04 source package in Bionic: Invalid Bug description: [Impact] X server crashes in certain cases on I+A hybrid machines with modesetting+amdgpu drivers. [Test case] Connect an external monitor, check that it doesn't crash X. [Regression potential] This commit was provided by AMD and reviewed by an NVIDIA engineer, and after a few iterations it got applied upstream. We'll test it with many driver combinations (modesetting+amdgpu, m+nvidia, m+m...) to check that they all (still) work. -- Copied from a private bug: - Steps to see the issue: 1. Connect a monitor to UUT via HDMI port Expected Result: Video outputs successfully in the monitor Actual Result: X crashes into a login screen - BIOS: 0.7.3 - AMD driver release: 18.10, 18.20RC8 and 18.20RC9 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg-server/+bug/1789913/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
