Bug 2029769

Summary:	fbdev Xorg driver no longer works as a fallback with unsupported hardware
Product:	Red Hat Enterprise Linux 9	Reporter:	Olivier Fourdan <ofourdan>
Component:	xorg-x11-server	Assignee:	Adam Jackson <ajax>
Status:	CLOSED ERRATA	QA Contact:	Peter Kopec <pekopec>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	9.0	CC:	csoriano, ndegraef, tpelka, xiaolong.wang, yijun_shen
Target Milestone:	rc	Flags:	pm-rhel: mirror+
Target Release:	9.0
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	xorg-x11-server-1.20.11-9.el9	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-05-17 12:53:07 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	1880082
Deadline:	2022-02-07

Description Olivier Fourdan 2021-12-07 09:41:23 UTC

Created attachment 1845040 [details]
Xorg.log

Description of problem:

Since the fix for bug 1988922 (closed as 2000921), the fbdev driver fails to probe the device and therefore cannot be used.

This is somehow expected considering that the fix for bug 1988922 removed the old device Probe() call from xf86CallDriverProbe() in the xserver and the fbdev driver doesn't implement a platformProbe()

Yet, fbdev was useful as a fallback driver when a native DRM driver is not available (e.g. with the newest, not yet supported hardware).

An alternative would be to use simpledrm but CONFIG_DRM_SIMPLEDRM is not yet enabled in our kernels so we're left without any fallback if the graphics hardware is not supported.

Version-Release number of selected component (if applicable):

xorg-x11-dev-fbdev-0.5.0-10

How reproducible:

Always

Steps to Reproduce:
1. Boot system with nomodeset

Actual results:

A graphical login screen on Xorg using fbdev driver as fallback

Expected results:

A black screen

Additional info:

This bug is to mostly to raise awareness of the regression and keep a record of whatever decision we make.

Comment 2 Carlos Soriano 2021-12-16 14:00:38 UTC

Opening this BZ to multiple partners, please exercise caution to not disclose confidential information.

Comment 15 Peter Kopec 2022-02-03 12:19:39 UTC

with updated xorg-x11-server and nomodeset grub option system will display basic graphical interface

Comment 19 errata-xmlrpc 2022-05-17 12:53:07 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (new packages: xorg-x11-server), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2022:2414

Comment 20 Niels De Graef 2022-06-17 12:56:33 UTC

*** Bug 2043463 has been marked as a duplicate of this bug. ***