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I've some screen trouble with my computer, I use it with a KVM switch, but this switch seems to block the EDID detection of the screen, and as no screen is detected, after the boot (when the Ubuntu loading logo normally appear) the screen go sleep mode. But with nomodeset kernel option the vesa driver correctly detects the screen and it works but with limitations (no hardware acceleration, mouse flickering, no sleep mode...).

I've made many tests (xrandr, build my own Xorg.conf ...) and I finally found this kernel patch : drm: allow loading an EDID as firmware to override broken monitor So I've tried to compile my own kernel, and I've seen the Ubuntu default kernel already have this patch and configured to be compiled on the kernel.

config-3.2.0-24-generic:

CONFIG_DRM_KMS_HELPER=m
CONFIG_DRM_LOAD_EDID_FIRMWARE=y

So I've make an /etc/modprobe.d/drm-kms-helper.conf that contains:

cat /etc/modprobe.d/drm-kms-helper.conf
options drm_kms_helper edid_firmware=VGA1:edid/1680x1050.bin

But the problem is still there, when i boot the screen go off. Even if the configuration still to be applied:

cat /sys/module/drm_kms_helper/parameters/edid_firmware 
VGA1:edid/1680x1050.bin

I've also tried these settings:

=VGA-1:edid/1680x1050.bin
=edid/1680x1050.bin

On the Xorg.0.log the system as the same behavior as before:

[    21.832] (II) intel(0): EDID for output VGA1
[    21.837] (II) intel(0): EDID for output HDMI1
[    21.884] (II) intel(0): EDID for output DP1
[    22.012] (II) intel(0): EDID for output HDMI2
[    22.016] (II) intel(0): EDID for output HDMI3
[    22.064] (II) intel(0): EDID for output DP2
[    22.112] (II) intel(0): EDID for output DP3
[    22.112] (II) intel(0): Output VGA1 disconnected
[    22.112] (II) intel(0): Output HDMI1 disconnected
[    22.112] (II) intel(0): Output DP1 disconnected
[    22.112] (II) intel(0): Output HDMI2 disconnected
[    22.112] (II) intel(0): Output HDMI3 disconnected
[    22.112] (II) intel(0): Output DP2 disconnected
[    22.112] (II) intel(0): Output DP3 disconnected
[    22.112] (WW) intel(0): No outputs definitely connected, trying again...
[    22.112] (II) intel(0): Output VGA1 disconnected
[    22.112] (II) intel(0): Output HDMI1 disconnected
[    22.112] (II) intel(0): Output DP1 disconnected
[    22.112] (II) intel(0): Output HDMI2 disconnected
[    22.112] (II) intel(0): Output HDMI3 disconnected
[    22.112] (II) intel(0): Output DP2 disconnected
[    22.112] (II) intel(0): Output DP3 disconnected
[    22.112] (WW) intel(0): Unable to find connected outputs - setting 1024x768 initial framebuffer

The strange thing is as written in the log, a 1024x768 picture is present but don't wake up the screen. The only way t see it is to switch with the KVM from an activated computer to this one.

For now I don't know what tracks to follow, i'm lost.

My problem seems to come from hotplug problem. When i disable it, everythings goes well. See here for more details

John S Gruber
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Madmax
  • 71

3 Answers3

2

My problem seems to come from hotplug problem. When i disable it, everythings goes well. See here for more details

Madmax
  • 71
0

You may need to explicitly enable the video port using the kernel parameter video=VGA-1:e.

Carsten
  • 1
0

I see the patch is only 2 days old. If you can, I'd suggest that you wait until the patch has been accepted into Linus' tree and then incorporated into an upstream kernel that the Ubuntu kernel team creates. (I see he removed the last attempt to fix this because of problems it caused).

After it has been merged, you can try to use an Ubuntu mainline build from the updated tree--see this. It's a bit complicated, but not as complicated as building your own kernel or using dkms.

See also this question.

Community
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John S Gruber
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