Public bug reported: Two identical Lenovo E495 laptops with 20.04 installed. The problem occurred initially on the laptop that is having package upgrades applied regularly.
With dual monitors and the external monitor placed left or right the display has a blocked staircase effect shown in the attached photograph, and seems related to https://gitlab.freedesktop.org/xorg/driver/xf86-video-amdgpu/-/issues/10 More detailed investigation suggests it only happens when the X coordinate of the two monitors is different. The symptom looks like an off-by-one error because it appears as if the display is divided into, say, 10 rows and 15 columns but the first row has 16 'columns' worth of blocks on it and so wraps to the beginning of the 2nd row, and so on. On the laptop without package upgrades being applied this didn't happen. So I upgraded it (314 packages) and restarted and it too sees the same problem. I suspected libxcomposite1 and downgraded it to 1:0.4.5-0ubuntu1 but that didn't solve it. I now suspect libxcb but so far haven't been able to prove it. ** Affects: libxcb (Ubuntu) Importance: Undecided Status: New ** Attachment added: "Blocked Staircase across two monitors" https://bugs.launchpad.net/bugs/1873895/+attachment/5357157/+files/IMG_0023.JPG -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to libxcb in Ubuntu. https://bugs.launchpad.net/bugs/1873895 Title: Regression: block staircase display with side-by-side monitors Status in libxcb package in Ubuntu: New Bug description: Two identical Lenovo E495 laptops with 20.04 installed. The problem occurred initially on the laptop that is having package upgrades applied regularly. With dual monitors and the external monitor placed left or right the display has a blocked staircase effect shown in the attached photograph, and seems related to https://gitlab.freedesktop.org/xorg/driver/xf86-video- amdgpu/-/issues/10 More detailed investigation suggests it only happens when the X coordinate of the two monitors is different. The symptom looks like an off-by-one error because it appears as if the display is divided into, say, 10 rows and 15 columns but the first row has 16 'columns' worth of blocks on it and so wraps to the beginning of the 2nd row, and so on. On the laptop without package upgrades being applied this didn't happen. So I upgraded it (314 packages) and restarted and it too sees the same problem. I suspected libxcomposite1 and downgraded it to 1:0.4.5-0ubuntu1 but that didn't solve it. I now suspect libxcb but so far haven't been able to prove it. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libxcb/+bug/1873895/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
