Bug 1679801 - udev not tagging efifb fb0 as master-of-seat
Summary: udev not tagging efifb fb0 as master-of-seat
Status: CLOSED DUPLICATE of bug 1683197
Alias: None
Product: Fedora
Classification: Fedora
Component: systemd
Version: 29
Hardware: aarch64
OS: Unspecified
Target Milestone: ---
Assignee: systemd-maint
QA Contact: Fedora Extras Quality Assurance
Depends On:
Blocks: ARMTracker
TreeView+ depends on / blocked
Reported: 2019-02-21 21:56 UTC by Jeremy Linton
Modified: 2019-05-02 20:07 UTC (History)
9 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
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Clone Of:
Last Closed: 2019-05-02 20:07:56 UTC
Type: Bug

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Bugzilla 1683197 0 unspecified CLOSED gdm fails to start with "nomodeset" on BIOS installs due to lack of framebuffer / master-of-seat device 2021-02-22 00:41:40 UTC

Description Jeremy Linton 2019-02-21 21:56:06 UTC
Description of problem: It seems that the window managers (sddm/gdm) are now activly checking the CanGraphical property from logind. This means they fail to start X on seats that don't have this properly. The efifb device exports a perfectly functional graphical framebuffer which tends to get taken over by native linux drivers (amdgpu/etc). If that doesn't happen then X can go ahead and start on the efifb device anway but with fixed resolution/color depth. AKA switching the DM to xdm allows normal login.

Version-Release number of selected component (if applicable): F29, sddm 0.18.0-1, systemd-udev 239-11. kernel-4.20.10-200

How reproducible: 100% with UEFI-Rpi firmware and latest fedora. I suspect its probably reproducable on any UEFI system where a dedicated kernel module doesn't take over the efifb device. AKA modprobe.blacklist=amdgpu or noveau leaves the efifb in place, and it never gets cangraphcial set.

Steps to Reproduce:
1. Grab RPI+upstream EDK2 firmware for rpi, build/install machine with f29
2. check `loginctl show-seat seat0` CanGraphical=XXX
3. Note `loginctrl seat-status seat0` 
                   graphics:fb0 "EFI VGA"

Actual results:
# loginctl show-seat seat0

Expected results:
Cangraphical should be set on working fbX devices.

Comment 1 Jeremy Linton 2019-02-21 21:59:23 UTC
BTW: SDDM & the rpi in this config works in a basic F29 install, its only after doing an upgrade does it start to fail. Not sure if it was SDDM that caused the problem or systemd-udev or something else irritating the problem (its not the kernel, booting the older kernel displays the same problem).

Comment 2 Peter Robinson 2019-02-24 23:11:10 UTC
udev is now part of systemd

Comment 3 Jeremy Linton 2019-05-02 20:07:56 UTC
As this problem was reproduced on x86, was causing a lot of problem, I'm going to dupe this against the gdm changes to remove the master-of-seat check.

*** This bug has been marked as a duplicate of bug 1683197 ***

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