sddm flashing issues on nvidia (lubuntu)
Originally filed at https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1895905 Also reported by user at https://discourse.lubuntu.me/t/login-screen-flashes/1634
** background & actual result
Clean install of Lubuntu (a QA-test install) on dell [optiplex] 990 (i7-2600, 16gb, nvidia geforce gt 6600 gt) on first login though, the greeter (sddm) has areas of the screen flashing white/black/white/black.. on an interval like a ":" on a clock between minutes & seconds "12:00"
The (1) session drop down, (2) layout drop down, & (3) user box (picture, my username & password entry area)
In the photograph they all appear as black; they flash WHITE alternatively, and that screen should have no black on it at all.
** expected result
No flashing should occur
** Cards impacted
- nvidia G72 [GeForce 7300 LE]
- nvidia geforce 6600gt
- winfast clone of nvidia 7600gt
** Additional information
This wasn't noticed before Ubuntu 19.10 or the 5.3 kernel (noticed first on i386)
The same boxes (6600gt & 7600gt) also have issues with Kubuntu as described with bug report https://bugs.launchpad.net/ubuntu/+source/kubuntu-meta/+bug/1891408, initially filed on 18.04.5 (using the 5.4 HWE kernel/i386) but same issue using 5.8 and hirsute/21.04 alpha/amd64. The issue could be the same, that issue in Kubuntu impacts all of Kubuntu experience, and not just input-areas like
sddm. I was asked to file upstream on the sddm bug report, thus this.
For video please see https://photos.google.com/share/AF1QipN0pivvzbpFrQGTWGDHWDp5xix4VI7Nf-vz6o47Xfh65eh9sn8CWoSKVorADrNz3g?key=YTVhbWdRX0xkV2hiUEp4T1RzRHZyWFFSMDNlbzdR reported by user on the Lubuntu discourse site (https://discourse.lubuntu.me/t/login-screen-flashes/1634/6?u=guiverc) Note: that user (7300le) sees characters in the background of the black; I only saw pure black on my two (6600gt & 7600gt)