iMac G5 20' + gutsy : shifted display

[guillaumeh]

I've installed a Ubuntu Gutsy on a iMac G5. The screen is a 20 inches, with a resolution of 1680x1050. The installation went mostly fine, but the display of the X server is a little shifted to the right: the first ~20 columns on the left of the screen are actually the last 20 columns of the display, and the rest is shifted to the right.

When I use the terminal (ctrl+alt+f1), the display by framebuffer is perfect.

I have tried to start xorg with the "vesa" driver once, but it did not start.

Here is what lspci says about the graphic card:


0000:f0:10.0 VGA compatible controller: nVidia Corporation NV34M [GeForce FX Go5200] (rev a1)


Here is the xorg.conf file:


# xorg.conf (xorg X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section "Files"
EndSection

Section "InputDevice"
Identifier "Generic Keyboard"
Driver "kbd"
Option "CoreKeyboard"
Option "XkbRules" "xorg"
Option "XkbModel" "pc105"
Option "XkbLayout" "fr"
Option "XkbVariant" "mac"
Option "XkbOptions" "lv3:ralt_switch"
EndSection

Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
Option "Device" "/dev/input/mice"
Option "Protocol" "ImPS/2"
Option "ZAxisMapping" "4 5"
Option "Emulate3Buttons" "true"
EndSection

Section "InputDevice"
Driver "wacom"
Identifier "stylus"
Option "Device" "/dev/input/wacom"
Option "Type" "stylus"
Option "ForceDevice" "ISDV4" # Tablet PC ONLY
EndSection

Section "InputDevice"
Driver "wacom"
Identifier "eraser"
Option "Device" "/dev/input/wacom"
Option "Type" "eraser"
Option "ForceDevice" "ISDV4" # Tablet PC ONLY
EndSection

Section "InputDevice"
Driver "wacom"
Identifier "cursor"
Option "Device" "/dev/input/wacom"
Option "Type" "cursor"
Option "ForceDevice" "ISDV4" # Tablet PC ONLY
EndSection

Section "Device"
Identifier "nVidia Corporation NV34M [GeForce FX Go5200]"
Driver "nv"
BusID "PCI:240:16:0"
EndSection

Section "Monitor"
Identifier "Color LCD"
Option "DPMS"
HorizSync 28-84
VertRefresh 43-60
EndSection

Section "Screen"
Identifier "Default Screen"
Device "nVidia Corporation NV34M [GeForce FX Go5200]"
Monitor "Color LCD"
DefaultDepth 24
SubSection "Display"
Modes "1680x1050" "840x524" "640x480"
EndSubSection
EndSection

Section "ServerLayout"
Identifier "Default Layout"
Screen "Default Screen"
InputDevice "Generic Keyboard"
InputDevice "Configured Mouse"

# Uncomment if you have a wacom tablet
# InputDevice "stylus" "SendCoreEvents"
# InputDevice "cursor" "SendCoreEvents"
# InputDevice "eraser" "SendCoreEvents"
EndSection


Has someone already had this problem ?

[stream303]

Wow - I'm just about to do that myself on my 20" iMac. Is yours one of the early ones like mine (no light-sensor?)

I'm pretty sure we can get that screen issue fixed.

I hate to admit it, but I went back to running OSX on it for only one reason - I couldn't control the brightness of the screen with Feisty. It was blazingly bright, just too much for me to handle.

If Gutsy can control a 20" iMac screen brightness, I'm ready to jump in with both feet and see about that screen-shift. Let me know please! :)

** Update **
Until I can get true brightness working, about the only thing I can do is take the edge off by slightly altering the gamma:
xgamma -gamma 0.9

"1" is the default for xgamma

[guillaumeh]

Wow - I'm just about to do that myself on my 20" iMac. Is yours one of the early ones like mine (no light-sensor?)

Yes, no light-sensor. It has a nvidia graphic card, while, from what I have read, the most reccent ones have an ATI.

I'm pretty sure we can get that screen issue fixed.


I hate to admit it, but I went back to running OSX on it for only one reason - I couldn't control the brightness of the screen with Feisty. It was blazingly bright, just too much for me to handle.

If Gutsy can control a 20" iMac screen brightness, I'm ready to jump in with both feet and see about that screen-shift. Let me know please! :)

I don't have any particular problem with brightness, I'm running XFCE and I haven't changed anything about this setting.

Also, I must add that the system feels very slow.

[stream303]

I don't have any particular problem with brightness, I'm running XFCE and I haven't changed anything about this setting.

Also, I must add that the system feels very slow.

Yup, I've got the same box. The shift is slightly annoying and I think I'm getting used to it. I just run with a solid color background and don't maximize my apps, but stretch them myself since we have so much real estate. I just love the overall look of the screen. It may not be fast, but is fantasticly sharp, especially when you add
Option "FPDither" "true"

to the device section right under the nv driver in xorg.conf

The iMac was pretty snappy when I ran Debian Etch on it with Fluxbox as the WM. But I needed the convenience of a large gui, so I don't mind the slight slowness of a full Ubuntu install. Just don't run glxgears or you'll cry. :)

If I come up with a fix for the display, you'll be the first to know...

[stream303]

Ok, I just loaded Feisty on the iMac. No problems with the display, nice and centered. The xorg.conf file looks to be the same as Gutsy.

This time with Feisty, I ran xvidtune. It would not move the display. I even changed resolution to 1400 x 1050 which provided a great looking pillarbox but xvidtune couldn't move that either. Ok, at least the lack of movement wasn't specific to gutsy.

At any rate, with the working Feisty, I got this modeline from xvidtune:

ModeLine "1680x1050" 147.14 1680 1784 1968 2256 1050 1051 1054 1087

Modelines get placed in your "Monitor" section of xorg.conf

Now that I have Feisty going and fully updated (I couldn't help myself), I'm too chicken to blow it all away back to Gutsy to see if this works. I wonder if xvidtune on Gutsy shows the same thing. I didn't document it... argh

[guillaumeh]

stream303: the modelines don't change anything.

[stream303]

Drat. Ok, possibly X11 or Gnome issues... more searching. :)

[guillaumeh]

Drat. Ok, possibly X11 or Gnome issues... more searching. :)
I'm using XFCE, and by the way, you can define workspace margins in XFCE. This enables to have maximised windows that remain inside the non-shifted area.

[tstack77]

Drat. Ok, possibly X11 or Gnome issues... more searching. :)

Not a GNOME issue. I installed kubuntu and had the same screen shift with the live cd.

[stream303]

Thanks guys, that's good to know. I really miss the latest Gimp 2.4.x and am not holding my breath for a backport to Feisty, so I may reinstall Gutsy sooner than later. :)

[tstack77]

I just upgraded to Gutsy from feisty for the hell of it...no luck, screen is screwed. Oh well, back to feisty i go till april.

[stream303]

No shame going back to Feisty!

I found another problem with the display: when I minimize apps, they disappear, only to be seen on a quick shutdown screen.

The quick workaround for disappearing minimized apps on Gutsy is to add "window switcher" panel applet to get your apps back.

This video thing is driving me nuts so i'm going to have to take a break. Now that it shows up in Heron-alpha, I'm bummed. :(

I guess I could live with workarounds, but I don't want to. Waaahh.

[stream303]

This post could be related to an Ubuntu bug filed at: https://bugs.launchpad.net/ubuntu/+bug/189844 . ---------------------------- . .
SOLVED!!

I am so happy to report that my G5 iMac is now running Gutsy with a normal display that is not shifted anymore. The problem was the new nvidia driver that came with Gutsy and also the Hardy Heron alpha.

How I fixed it:

Downgraded to the Feisty nv video driver.

From my working Feisty install, I copied

/usr/lib/xorg/modules/drivers/nv_drv.so

to the same directory on my Gutsy box.

Life is good! I replied to the bug-report initially about Hardy, but it applies to Gutsy as well.

[stream303]

Just in case you were wondering:

I tried Debian Lenny testing and it also has the same problem, so hopefully the bug report will trickle down from freedesktop.org to all ppc distros.

BTW, Lenny testing as of today was a total failure with either internal or external cd installation. Had to do a dist-upgrade of etch to Lenny just to see that this problem with the new nv driver still exists.

[RichardBronosky]

Downgraded to the Feisty nv video driver.

Any idea how to do this if you don't have the luxury of a Feisty install to copy from? What version of the driver is it?

I'm dissatisfied with OS X performance on my 20" iMac G4, so I'm trying out the Hardy Heron Live CD. I think it could be a bit of a challenge to get this worked out, but I'm not blowing over my OS X install until I know I can get this to work.

[stream303]

Problem is that Hardy, and all other distros using the newer xorg have this issue, since the nv driver problem is coming from freedesktop.org. It's been reported and verified, so I'm hoping to see a fix trickle back down.

Even though I just copied my nv driver from feisty to a thumb-drive for installation on Gutsy, you might be able to pick up xserver-xorg-video-nv from here:

http://packages.ubuntu.com/feisty/x11/

Remember to make the file permissions the same as the one you are replacing. I have the feeling that we won't be seeing any updates for this issue with Gutsy -- this isn't really the proper way to do it if you are expecting an update in Gutsy, but it works. Not elegant, but at this point....

Unfortunately this technique does not seem to work with Hardy - the old nv driver seems too far out of reach now.

That being said, I find it livable. Slightly annoying, but not a showstopper. Maybe see what it looks like using the live desktop-cd installer to you.

[walker9010]

I'm experiencing this issue too...but I'm running Hardy. Any suggestions for a fix?

[stream303]

I reported it as a bug at freedesktop.org, and got a response from a dev acknowledging the issue in the latest nv driver. So for now, I guess we have to wait for it to trickle down from them.

I like Hardy too much to go back to a Gutsy / Feisty driver setup, so I try not to let it drive me too crazy. :)

Although this isn't a fix for the screen-shift, have you tried adding the FPDither option to your xorg.conf:

Section "Device"
Identifier "Configured Video Device"
BusID "PCI:240:16:0"
Option "FPDither" "true"
EndSection

and restarting X? Helps to make the small details and fonts look really nice on our nv-driven lcd iMacs.

[walker9010]

i did---definetly looks better. thanks for your help!