#781932 xserver-xorg-video-intel: laptop display unusable (blank) if external monitor is connected

Package:
xserver-xorg-video-intel
Source:
xserver-xorg-video-intel
Description:
X.Org X server -- Intel i8xx, i9xx display driver
Submitter:
Chris Bainbridge
Date:
2015-04-05 21:09:08 UTC
Severity:
important
#781932#5
Date:
2015-04-05 01:07:08 UTC
From:
To:
Dear Maintainer,

Hardware: IvyBridge HD4000 GPU on Macbook Pro 13

To reproduce:

- Connect an external monitor on DP
- Boot jessie
- Log in to Gnome
- Laptop display immediately goes blank

This bug appears to be fixed in the latest upstream git. It is not
known at which point it got fixed. xorg.log with working upstream git:

 (--) intel(0): Output eDP1 using initial mode 2560x1600 on pipe 0
 (--) intel(0): Output DP2 using initial mode 1680x1050 on pipe 1

xorg.log with non-working jessie driver:

 (II) intel(0): Output eDP1 using initial mode 1680x1050
 (II) intel(0): Output DP2 using initial mode 1680x1050

So the issue might be that the driver attempts to use the incorrect
external monitor resolution 1680x1050 for the laptop display. Though
xrandr reports the laptop display resolution 2560x1600 is in use:

Screen 0: minimum 320 x 200, current 4240 x 1600, maximum 8192 x 8192
eDP1 connected primary 2560x1600+0+0 (normal left inverted right x axis y axis)
286mm x 179mm
   2560x1600     59.97*+
   2048x1536     60.00
   1920x1440     60.00
   1856x1392     60.01
   1792x1344     60.01
   1920x1200     59.95
   1920x1080     59.93
   1600x1200     60.00
   1680x1050     59.95    59.88
   1600x1024     60.17
   1400x1050     59.98
   1280x1024     60.02
   1440x900      59.89
   1280x960      60.00
   1360x768      59.80    59.96
   1152x864      60.00
   1024x768      60.00
   800x600       60.32    56.25
   640x480       59.94

Attempting to manually change the mode with xrandr does nothing (not
surprising, as xrandr reports the mode is already correct).
#781932#12
Date:
2015-04-05 12:54:19 UTC
From:
To:
Why was the severity downgraded from 'serious'?

Isn't the laptop display being non-functional a serious bug? One which
could potentially impact every Debian laptop user with an Intel GPU
and an external monitor? Which, presumably, would be quite a few
people.
#781932#17
Date:
2015-04-05 14:20:29 UTC
From:
To:
No, an issue with the display of a single laptop is not serious.

Cheers,
Julien
#781932#22
Date:
2015-04-05 14:29:58 UTC
From:
To:
How do you know the issue is only with the display of a single laptop?
Have you tested any other (Intel) laptops with an external monitor?
Particularly where the resolution of the laptop does not match that of
the external monitor?
#781932#27
Date:
2015-04-05 14:32:10 UTC
From:
To:
1) if this was a general issue we'd have received a dozen reports by now
2) my laptop works just fine

Cheers,
Julien
#781932#32
Date:
2015-04-05 16:24:49 UTC
From:
To:
It is unlikely that this kind of bug would impact just one single
laptop. It is more likely to impact a broader class, at the least
"IvyBridge Macbook", but possibly more broadly just "IvyBridge laptop"
or perhaps "SNB/IVB/HSW laptop". Without testing and/or understanding
of the cause of the bug, I don't see how you can draw the conclusion
that the bug only occurs on a single laptop.
#781932#39
Date:
2015-04-05 20:58:01 UTC
From:
To:
tags 781932 moreinfo
stop

hello,

Please do stop producing entropy.
The bug severity is up to the judgment of the maintainers
in the regular case that the bug submitter misunderstood it
(which is the case here).

It would be more helpful to narrow down which newer package
version starts to work for this laptop (as from this one could
narraw down the possible patches). Which versions of intel on
http://snapshot.debian.org/ did you try?

best,