Screen is dark and brightness cannot adjust.

[Franz Hsieh]

I installed Ubuntu 16.04 LTS on my HP 705 G2 all-in-one machine. It is an AMD kaveri graphic based platform. After installation is done my screen is dark (but still can see something on it so I can file this bug). The brightness is not functional (stays dark).

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3
ProcVersionSignature: Ubuntu 4.4.0-23.41-generic 4.4.10
Uname: Linux 4.4.0-23-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
BootLog: [ OK ] Started LSB: Set the CPU Frequency Scaling governor to "ondemand".
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: compiz
CompositorUnredirectDriverBlacklist: '(nouveau|Intel).*Mesa 8.0'
CompositorUnredirectFSW: true
CurrentDesktop: Unity
Date: Wed Jun 1 03:02:00 2016
DistUpgraded: Fresh install
DistroCodename: xenial
DistroVariant: ubuntu
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] Kaveri [Radeon R7 Graphics] [1002:130f] (rev d7) (prog-if 00 [VGA controller])
   Subsystem: Hewlett-Packard Company Kaveri [Radeon R7 Graphics] [103c:805c]
InstallationDate: Installed on 2016-06-01 (0 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
MachineType: HP HP EliteOne 705 G2 23-in Touch AiO
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-23-generic.efi.signed root=UUID=4b6b12fb-1689-40f1-9cb7-adc76b80245b ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/05/2016
dmi.bios.vendor: HP
dmi.bios.version: N16 Ver. 02.12
dmi.board.name: 805C
dmi.board.vendor: HP
dmi.board.version: KBC Version 05.22
dmi.chassis.asset.tag: MXL6123GLK
dmi.chassis.type: 13
dmi.chassis.vendor: HP
dmi.modalias: dmi:bvnHP:bvrN16Ver.02.12:bd05/05/2016:svnHP:pnHPEliteOne705G223-inTouchAiO:pvr:rvnHP:rn805C:rvrKBCVersion05.22:cvnHP:ct13:cvr:
dmi.product.name: HP EliteOne 705 G2 23-in Touch AiO
dmi.sys.vendor: HP
version.compiz: compiz 1:0.9.12.2+16.04.20160526-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.67-1ubuntu0.16.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 11.2.0-1ubuntu2
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 11.2.0-1ubuntu2
version.xserver-xorg-core: xserver-xorg-core 2:1.18.3-1ubuntu2.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.10.1-1ubuntu2
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:7.7.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.12-1build2
xserver.bootTime: Wed Jun 1 03:00:27 2016
xserver.configfile: default
xserver.errors:

xserver.logfile: /var/log/Xorg.0.log
xserver.version: 2:1.18.3-1ubuntu2.2
xserver.video_driver: radeon

[Alberto Milone (albertomilone)]

Can you try my kernel, please?

Make sure to install both linux-image and linux-image-extra.

What my kernel does is enable support for Kaveri in the amdgpu driver.

Also, please attach the dmesg output when running the new kernel.

http://people.canonical.com/~amilone/cik-enabled/

[Pascal Morin (pcm689)]

+Franz, Emily, Jamie, Anthony

Alberto,

Franz is going to try your kernel and keep you updated on LP.

Thank you

Pascal Morin -
On 01/06/2016 21:22, Alberto Milone wrote:
> Can you try my kernel, please?
>
> Make sure to install both linux-image and linux-image-extra.
>
> What my kernel does is enable support for Kaveri in the amdgpu driver.
>
> Also, please attach the dmesg output when running the new kernel.
>
> http://people.canonical.com/~amilone/cik-enabled/
>

[Franz Hsieh (franz-hsieh)]

@Alberto,

Screen is still dark with your patched kernel.

[Alberto Milone (albertomilone)]

It seems that the system is still using the radeon driver:

[ 1.793412] [drm] radeon kernel modesetting enabled.

You might want to blacklist radeon, and try again (I'm going to need the new logs too)

[Kristin Chuang (kristinchuang)]

@Alberto, @Franz,

Blacklisted Radeon with the following:
$ echo 'blacklist radeon' | sudo tee /etc/modprobe.d/blacklist-radeon.conf
$ sudo reboot

Results:

1. Saw the following in dmesg output:
[ 3.914125] [drm] amdgpu kernel modesetting enabled.

2. But the screen is still dark and still cannot modify brightness level via brightness settings.