Created attachment 94569 [details]
Output from the glxinfo command

Forgot to say that if I build Intel drivers with "sna" USE flag disabled and with "uxa" USE flag enabled both problems disappear (offset and trails).

Created attachment 94570 [details]
intel_reg_dumper log

I used intel-gpu-tools from Git.

Poking Chris ...

I just updated my system. At the moment I have:
- x11-base/xorg-server-1.15.0
- gnome-base/gdm-3.10.0.1
- x11-drivers/xf86-video-intel-2.99.910
- media-libs/mesa-10.1.0

I still have this problem, anyway.

There was nothing in the logs to suggest any foul play anywhere on the system. My two theories were either the modesetting registers were programmed wrong by the kernel causing the offset, or that it was being rendered into the wrong position by the ddx. Everything looks self-consistent.

Time to try random settings. In Section "Device" of /etc/X11/xorg.conf, try

Option "AccelMethod" "blt"
Option "DRI" "off"
Option "VSync" "false"
Option "SwapbuffersWait" "false"
Option "TripleBuffer" "false"

and see if any those (individually) have any effect.

All options lead to the same offset problem, except the second one (Option "DRI" "off") that instead lead to the following GDM error:

> Oh no! Something has gone wrong. A problem has occurred and the system can't recover. Please log out and try again.

I'm going to attach Xorg and GDM error logs from this last case.

Created attachment 95586 [details]
Xorg log when Option "DRI" "off" is added to xorg.conf

Created attachment 95587 [details]
GDM log when Option "DRI" "off" is added to xorg.conf

(In reply to comment #7)
> All options lead to the same offset problem, except the second one (Option
> "DRI" "off") that instead lead to the following GDM error:
> 
> > Oh no! Something has gone wrong. A problem has occurred and the system can't recover. Please log out and try again.
> 
> I'm going to attach Xorg and GDM error logs from this last case.

That's just gnome-shell(gdm) being useless.

Can you grab a screenshot of the login screen, and also a photograph? The first will show if it is a rendering error, the later may give some clue as to what the error is (if in the display path).

Created attachment 95663 [details]
GDM screenshot

Created attachment 95664 [details]
GDM photograph

I took this photograph with my webcam. I'm sorry for the low quality, but I don't have a camera or a smartphone. Anyway the black strip at the right of the screen is visible.

Can you please reproduce the issue and then grab the output from intel_reg_dumper (intel-gpu-tools, latest git recommended) and from /sys/kernel/debug/dri/0/i915_gem_framebuffer and attach it to this bug report?

I'm sorry but unfortunately I'm not using GNOME and GDM anymore and I can't do tests. Anyway there is the possibility I could switch back to GNOME in the (near?) future. I have mixed feelings about GNOME, and I haven't make up my mind yet.

Created attachment 98371 [details]
intel_reg_dumper output

Created attachment 98372 [details]
content of /sys/kernel/debug/dri/0/i915_gem_framebuffer

I decided to switch back to Gentoo and GNOME. Sorry for the wasted time. I used intel-gpu-tools from git. Current version of relevant packages:
- mesa-10.1.1
- xorg-server-1.15.1
- gdm-3.10.0.1-r1
- xf86-video-intel-2.99.911

The recent output is with fbcon active, not gnome, so the register settings are not helpful.

I just started GDM, switched to a terminal with ctrl+alt+f1 and then obtained the data. Should I do something else perhaps?

I have a very similar problem on Ubuntu 14.04. After having logged in the screen shifts to the left and a black strip appears on the right. I think this is interesting because Ubuntu uses Unity and LightDM instead of GNOME and GDM. I'm going to attach a photo of my screen and the Xorg log.

Created attachment 99114 [details]
Xorg log under Ubuntu 14.04

Created attachment 99118 [details]
Photo of the screen with Ubuntu 14.04 running

I forgot to tell you that at the moment my Ubuntu system uses xserver-xorg-video-intel version 2:2.99.910-0ubuntu1. I also tried to install the newly released Intel Graphics Installer 1.0.5 for Ubuntu 14.04, but a GPG related error prevent me to do that. I'll try again when it will be fixed.

Another test: What are the extents of the cursor? Does it go right to the right hand edge of the screen?

My current thinking is that this is just a CRTC misconfiguration.

No, it is not possible to move the cursor on the black strip at the right. I tried both in Ubuntu and in Gentoo and the result is the same.

I also noted that in Ubuntu the screen is not "stable" because sometimes I see the black strip at the right but some other times the screen is OK and there's no black strip. This happens in the same session, without logging off. Also in Ubuntu the screen turns off sometimes for a few seconds, while in Gentoo this never happens. I can't understand if there's some trigger for this behaviour. I should do some other tests later.

That makes me confident in moving the blame further down the stack...

What's the kernel version here? Can you please try to retest with latest upstream (preferrably at least 3.15-rc ...)?

Ubuntu kernel version is 3.13.0-24-generic. Gentoo kernel version is 3.14.4. On Gentoo I still have the same version of the packages listed in comment 18.

I tried building a vanilla kernel on Gentoo (not gentoo-sources but directly from kernel.org). I used version 3.15.0-rc5 (latest version available). The system still exhibits the same problem with Intel drivers enabled at boot.

I managed to install Intel Graphics Installer 1.0.5 on Ubuntu, but the offset problem is still there. It doesn't look the installer upgraded something significant, anyway.

-----

Added:
    i965-va-driver:amd64 (1.3.0-1ubuntu1)
    libva-drm1:amd64 (1.3.0-2)
    libva-egl1:amd64 (1.3.0-2)
    libva-glx1:amd64 (1.3.0-2)
    libva-intel-vaapi-driver:all (1.3.0-1ubuntu1)
    libva-tpi1:amd64 (1.3.0-2)
    libva-wayland1:amd64 (1.3.0-2)
    libva-x11-1:amd64 (1.3.0-2)
    libva1:amd64 (1.3.0-2)
    vainfo:amd64 (1.3.0-2)
    
Upgraded:
    intel-gpu-tools:amd64 (from 1.3-0ubuntu2 to 1.6-1)

I updated my Gentoo system, but I still have this problem. I'm now using the following packages:
- x11-base/xorg-server-1.15.1 
- sys-kernel/gentoo-sources-3.15.2 
- gnome-base/gdm-3.12.2 
- x11-drivers/xf86-video-intel-2.99.912-r1

Could you please grab and attach here a register dump with intel_reg_dumper of intel-gpu-tools?

I already did that (see the previous comments and attachments) but if you want I can do that again. The problem is I'm not using GNOME/GDM anymore on my Gentoo system, and I can't put it back due to compatibility and stability problems. But I can install Ubuntu (it has the same offset problem), update it and use intel_reg_dumper on it. Is this OK? Can I proceed?

Created attachment 107882 [details]
output from intel_reg_dumper

Sorry for the delay. I changed my mind again and switched back to Ubuntu. intel_reg_dumper is from git.

After log in I got an error message from Ubuntu:
> Could not switch the monitor configuration
> could not set the configuration for CRTC 63

I can't reproduce the bug anymore. I managed to get rid of the horizontal offset by activating the "Auto Adjust" function on my monitor's OSD. I definitively should have tried that much earlier. I'm sorry.

I noticed that my monitor automatically auto-adjusts itself from time to time. It's not that bothersome, but it's a sign that there's still something that doesn't perfectly work.

(In reply to Francesco Turco from comment #37)
> I noticed that my monitor automatically auto-adjusts itself from time to
> time. It's not that bothersome, but it's a sign that there's still something
> that doesn't perfectly work.

VGA is a black art when trying to autosync with panels. Might be that the bios and linux don't pick the exact same mode and that tends to confuse cheaper panels sufficiently already. I don't think there's anything we can do here unfortunately. Thanks anyway for reporting this issue.