Precise GMA500 screen resolution and flicker

[Svante Jacobsen]

Started the Ubuntu 12.04 demo iso from USB on my Sony Vaio X

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu
Description: Ubuntu precise (development branch)
Release: 12.04
Beta 2

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center
?

3) What you expected to happen
The screen should be set to 1366x768 (wide).

4) What happened instead
Screen is either (initially) chopped off horizontally on the try/install page. When clicking to try, ubuntu is started with the resolution set to 1024x768 leaving the right/part of the screen impossible to reach and filled with garbage/static/part of VAIO-logo. Also unable to change the resolution in settings. Also the top part of screen flicker.

See attached photo.

[Svante Jacobsen (svante-jacobsen)]

All as described happened the first time i ran the "Try Ubuntu". I shut everything down and did everything exactly the same a second time to confirm and write this bug report.

Afterwards I have tried 2 more times (also exactly the same) and the screen resolution worked both times (nolonger an issue).

BUT - The Try/Install page is always split in the middle and the far top of the screen keeps flickering as described (to be exact, the entire screen is flickering with seemingly diagonal lines moving across light purple/orange/gray areas - difficult to describe but annoying to such degree that is affecting usability - almost as much as Unity :-).

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Svante Jacobsen (svante-jacobsen)]

On April 4 the screen resolution is still an issue. Some 50% of the times the system starts up with 1024x768. I haven't tried again since.

[Luis Sanjuán (luisj-sanjuan)]

I can confirm this bug with the same machine: non-native resolution and flickering, after installing the beta2 this morning.

A workaround for installation is to resort to the alternate-CD. Rebooting after finishing installion ends in black screen, but changing then into a console w/ CTL+ALT+F1 and restarting lightdm (sudo service lightdm restart) makes login screen accessible. Choosing there 2D-Desktop opens the Unity desktop, without "artifacts", but with the wrong resolution and the slight flickering already reported by @Svante. gnome-settings-daemon does not provide other resolutions.

By the way, adding "console=tty1" to grub default options does not resolve the problem, neither updating all the packages at their last version.

I keep investigating just in case, though kernel freeze is already done.

[Luis Sanjuán (luisj-sanjuan)]

More tests:

I've been able to reproduce the random behavior reported by @Svante. Sometimes the native resolution mode of the monitor (1366x768) is recognized, sometimes it does not, and the system falls to 1024x768.

As a workaround I've created a typical screen.conf section in /usr/share/X11/xorg.conf.d

Section "Screen"
    Identifier "Default Screen"
    Monitor " Configured Monitor"
    Device " Configured Video Device"
        SubSection "Display"
            Virtual 1366 768
        EndSubSection
EndSection

From then on I have not experienced the problem. Being a random behaviour it is dificcult to confirm the efficacy of this fix without a more thoroughly examination of log files and so on.

As to flickering, I think it is much less noticeable at reduced backlight levels. Backlight control is not activated by default in these Vaio machines. It must be pass a paramater from grub. I have config my grub file (/etc/default/grub) to do this:

GRUB_CMDLINE_LINUX_DEFAULT="pci=noacpi"

[Zygmunt Krynicki (zyga)]

Flickering and initial screen corrpution also affects VAIO-P (second generation), such as my VPCP11S1E

[Luis Sanjuán (luisj-sanjuan)]

Updating my last post

1) Resolution problem

The screen.conf workaround posted before seems to be completely reliable. No more resolution problems until now.

2) Brightness control to reduce flickering

As a matter of fact 'pci=noacpi' is not necessary. It is enough to pass this parameter from grub:

acpi_backlight=vendor

[Lukas Stark (catlx)]

Is it somehow possible to remove the flickering? In earlier versions (e.g. 9.10) the graphics are without this flickering out of the box.

[Mike (mfpl)]

I have already tried all possible variants changing the screen mode via xrandr, including the Modeline ( Modeline "1366x768" 74.06 1366 1429 1557 1663 768 768 769 775 -HSync +VSync) , that is proposed in the 10-emgd.conf, which was made especially for Vaio X.

Without changing anything, xrandr -q gives out following line:
LVDS-0 connected 1366x768+0+0 0mm x 0mm
   1366x768 29.9*+ 57.5

[Linux User #330250 (linuxuser330250)]

I have an ASUS Eee PC 1101HA.
Aside from the Atom Z520 processor it uses a GMA500 embedded graphics card which is part of the SCH US15W chipset, also known as "Poulsbo".

The interesting thing is: Ubuntu 12.04.4 LTS works out of the box and is reasonably fast.
Now I installed Ubuntu 14.04 LTS and graphics is alsmost unusable.
Also, it has a flickering from the start that I could not get rid of.

This specific 14.04 bug has already been reported:
https://lists.launchpad.net/gma500/msg00719.html
But since this is a mail archive, I wasn’t able to send a follow-up.

Is there any way to get the "old" but working driver back?

[Linux User #330250 (linuxuser330250)]

The flicker problem on 14.04 is connected to the gma500_gfx.ko kernel module. Someone named pmarques has already identified that the pixel clock is too low, and hopefully he’s working on it:
https://bugs.freedesktop.org/show_bug.cgi?id=78562

[Timo Aaltonen (tjaalton)]

obsolete driver, closing