I found that using the nomodeset kernel boot option disables i915 graphics driver, causing fallback to vesa graphics. This made all graphics artifacts go away for me on ascii, with all kernels I tested. The only two disadvantages I can think of with this approach is that it seems to break my computer's ability to suspend (see https://dev1galaxy.org/viewtopic.php?pid=8355#p8355). Also, some people report that with vesa graphics they cannot use multiple monitors at once (this doesn't affect me but I thought I'd mention it for completeness's sake).

I decided to stop fighting this and simply fetched and installed the kernel I was using on devuan jessie (linux-image-3.16.0-5-amd64). Lo and behold, no more video glitches. Woo-hoo!

When I look at all packages available in ascii-security, I see the same kernels represented:

$ grep ^Package: /var/lib/apt/lists/pkgmaster.devuan.org_merged_dists_ascii-security_main_binary-amd64_Packages | grep linux | grep amd64
---snip---
Package: linux-headers-4.9.0-3-amd64
Package: linux-headers-4.9.0-4-amd64
Package: linux-headers-4.9.0-5-amd64
Package: linux-headers-4.9.0-6-amd64
Package: linux-headers-amd64
Package: linux-image-4.9.0-3-amd64
Package: linux-image-4.9.0-4-amd64
Package: linux-image-4.9.0-5-amd64
Package: linux-image-4.9.0-6-amd64
Package: linux-image-amd64
---snip---

Therefore, it seems that all kernels kept in the main repository receive security upgrades through the security repository (if I'm drawing the wrong conclusion based on the above, someone please correct me).

I'll give 4.9.0-3 a shot. Thanks, Geoff.

I'd like to have my cake and eat it too, of course, but if I *have* to choose between automatic security upgrades and fixing a minor cosmetic issue then I'll take the upgrades.

Geoff

It turns out that kernels 4.13 and 4.14 from backports both have a graphics issue on my machine: Sometimes, rather randomly, I get a horizontal line across my screen below which there is no video output whatsoever. The line moves up and down for a few seconds before it goes away. This issue is more serious than what I was experiencing with ascii's default 4.9 kernel, so I went back to 4.9.

https://dev1galaxy.org/viewtopic.php?id=1794

The solution was a more recent kernel from backports.

Geoff

I'm on a T400 with libreboot and integrated intel graphics. The issue is that every few minutes some lines quickly flash near the bottom and center of my laptop's display. The lines disappear after a fraction of a second and do not cause any problems other than being an eyesore. It seems to make no difference what applications are open. This does not happen on Devuan Jessie.

All my packages are from the main repository, and I have no third-party apps. In other words, this is not a fancy machine with default kernel and vanilla assortment of packages.

I'm using the default ascii kernel:

bruno@thinkpad:~$ uname -a
Linux thinkpad 4.9.0-6-amd64 #1 SMP Debian 4.9.82-1+deb9u2 (2018-02-21) x86_64 GNU/Linux

Here are the relevant bits from lshw:

  *-core
       description: Motherboard
       product: 2767EA9
       vendor: LENOVO
       physical id: 0
       version: ThinkPad T400
       serial: R8795K5
     *-firmware
          description: BIOS
          vendor: coreboot
          physical id: 0
          version: CBET4000 1403e19
          date: 09/02/2016
          size: 1MiB
          capacity: 8128KiB
          capabilities: pci pcmcia upgrade bootselect acpi
        *-display:1 UNCLAIMED
             description: Display controller
             product: Mobile 4 Series Chipset Integrated Graphics Controller
             vendor: Intel Corporation
             physical id: 2.1
             bus info: pci@0000:00:02.1
             version: 07
             width: 64 bits
             clock: 33MHz
             capabilities: pm cap_list
             configuration: latency=0
             resources: memory:e5900000-e59fffff

Any ideas what this could be or how to troubleshoot it? My guess is that it has something to do with ascii's newer linux kernel.