I am trying to setup a dual screen configuration on debian 8 jessie with Gnome.
My computer has 3 graphical outputs : 2 displayport and 1 HDMI. I can’t manage to have two of this 3 outputs to work simultaneously.
output of xrandr is (with the other display on displayport):
xrandr: Failed to get size of gamma for output default Screen 0: minimum 1680 x 1050, current 1680 x 1050, maximum 1680 x 1050 default connected primary 1680x1050+0+0 0mm x 0mm 1680x1050 0.00* `
output of xrandr is (with hdmi working):
xrandr: Failed to get size of gamma for output default Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080 default connected primary 1920x1080+0+0 0mm x 0mm 1920x1080 0.00*
I also tried to use both displayport but it does not work either.
output of lshw -c videò:
*-display UNCLAIMED description: VGA compatible controller product: Intel Corporation vendor: Intel Corporation physical id: 2 bus info: <a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="1b6b78725b2b2b2b2b">[email protected]</a>:00:02.0 version: 06 width: 64 bits clock: 33MHz capabilities: pciexpress msi pm vga_controller bus_master cap_list configuration: latency=0 resources: memory:f6000000-f6ffffff memory:e0000000-efffffff ioport:f000(size=64)
(with both screens connected via displayport)
output of lspci -v -s0:0:2.0
00:02.0 VGA compatible controller: Intel Corporation Device 1912 (rev 06) (prog-if 00 [VGA controller]) Subsystem: Dell Device 06b9 Flags: bus master, fast devsel, latency 0, IRQ 255 Memory at f6000000 (64-bit, non-prefetchable) [size=16M] Memory at e0000000 (64-bit, prefetchable) [size=256M] I/O ports at f000 [size=64] Expansion ROM at <unassigned> [disabled] Capabilities: <access denied>
Answers:
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Method 1
Unfortunately Debian 8 as released doesn’t support mobile Broadwell or later very well, and you’ve got a Sky Lake system.
To fix things, you need to upgrade your kernel, using Jessie backports, and install firmware to enable full graphics support (so you’ll be adding the non-free backports repository).
First you need to add Jessie backports to your repositories, if it’s not already there:
echo deb http://http.debian.net/debian jessie-backports main contrib non-free > /etc/apt/sources.list.d/jessie-backports.list
(as root), then
apt-get update apt-get -t jessie-backports install linux-image-amd64 firmware-misc-nonfree
will install the current default backported kernel (4.7 as of this writing) and the accompanying firmware.
Once you’ve done that, you can remove xserver-xorg-video-intel (nowadays Intel GPUs don’t need a separate driver, they can use the kernel’s mode-setting support):
apt-get remove xserver-xorg-video-intel
Enabling backports is safe: newer packages are not picked up automatically from backports, you need to explicitly select them using -t jessie-backports as above (but once you’ve done that, updates to the upgraded packages are picked up by apt-get upgrade).
Method 2
In a similar system, I’ve succeeded in setting up two output which works great for any purpose (i.e watching videos in both screens).
For mirror screens:
xrandr --output LVDS-1 --mode 1366x768 --scale 1x1 --output VGA-1 --same-as LVDS-1 --mode 1920x1080 --scale 0.711x0.711 # Actually the whole desktop is 1366x768 , VGA-1 mode is set 1920X1080 but scaled (in reallity looks a little bit enlarged) to match 1366x768.
For Extended Desktop:
First run xrandr to get a list of displays with correct names, and the supported resolution configurations; then replace VGA-1 and LVDS-1 AND the resolutions in the command below, to suit:
xrandr --output VGA-1 --mode 1920x1080 --scale 1x1 --output LVDS-1 --mode 1366x768 --scale 1x1 --left-of VGA-1
All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0