X hangs after wake on Mobility Radeon x1400

[Boris Gjenero]

I have a Dell Inspiron 6400 with Mobility Radeon x1400. In Ubuntu 20.10 and earlier, wake from sleep worked properly. In Ubuntu 21.04, X does not work after wake from sleep. It fails in Plasma, Xfce, Openbox and Twm. With both Plasma and Xfce the screen is totally black. In all cases it is possible to use Control+Alt+F2 to go to a text console and use that. Generally it is possible to kill and restart X to get a usable GUI again.

I'm reporting this as a kernel bug because if I boot Ubuntu 21.04 with linux-image-5.8.0-48-generic from Ubuntu 20.10, then X works after wake from sleep.

ProblemType: Bug
DistroRelease: Ubuntu 21.04
Package: linux-image-5.11.0-13-generic 5.11.0-13.14
ProcVersionSignature: Ubuntu 5.11.0-13.14-generic 5.11.7
Uname: Linux 5.11.0-13-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.11-0ubuntu61
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: bgjenero 1095 F.... pulseaudio
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Sat Apr 3 12:20:38 2021
HibernationDevice: RESUME=UUID=2d7284cc-d0df-45d7-b0a1-e5a0a8128eb8
InstallationDate: Installed on 2012-01-19 (3362 days ago)
InstallationMedia: Xubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
Lsusb:
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Lsusb-t:
 /: Bus 05.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
 /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
 /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
 /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
 /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/8p, 480M
MachineType: Dell Inc. MM061
ProcFB: 0 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.11.0-13-generic root=UUID=d590f141-7b8d-421d-84b3-baa43181a241 ro resume=/dev/sda5
RelatedPackageVersions:
 linux-restricted-modules-5.11.0-13-generic N/A
 linux-backports-modules-5.11.0-13-generic N/A
 linux-firmware 1.196
SourcePackage: linux
UpgradeStatus: Upgraded to hirsute on 2021-04-02 (1 days ago)
dmi.bios.date: 06/13/2007
dmi.bios.release: 1.7
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A17
dmi.board.name: 0XD720
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.ec.firmware.release: 1.7
dmi.modalias: dmi:bvnDellInc.:bvrA17:bd06/13/2007:br1.7:efr1.7:svnDellInc.:pnMM061:pvr:rvnDellInc.:rn0XD720:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: MM061
dmi.sys.vendor: Dell Inc.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Boris Gjenero (boris-gjenero)]

Wake from sleep works in Xfce and Plasma in Ubuntu 21.04 when using kernel 5.12.0-051200rc5-generic from https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.12-rc5/

[Boris Gjenero (boris-gjenero)]

Wake worked with kernel 5.11.0-16-generic. So, I guess this is fixed.