xrandr: Failed to get size of gamma for output default

czezz · 05-28-2020, 04:13 AM

Slackware 14.2 x64 (guest VM)
VirtualBox (5.1.38) - no VirtualBox Guest Additions yet.

I get an error/warning when issue xrandr command:

Code:

# xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 400, current 1024 x 768, maximum 1024 x 768
default connected 1024x768+0+0 0mm x 0mm
   1024x768      61.00* 
   800x600       73.00  
   640x480       86.00  
   640x400       86.00

I tried --addmode as some people reported to overcome this problem this way but in my case it doesnt help.
Any ideas what else to try?

Code:

# xrandr --monitorlist
xrandr: Failed to get size of gamma for output default
Monitors: 1
 0: +default 1024/271x768/203+0+0  default

# xrandr --addmode default 1024x768
xrandr: Failed to get size of gamma for output default

mrmazda · 05-30-2020, 10:07 PM

I'm a hardware user only, so don't know what difference using virtualization or having guest additions available might make, but otherwise, usually the failure to get any information about output default means the in use DDX (X GPU driver, not kernel GPU driver) is a suboptimal or fallback one, such as VESA or FBDEV, or else, KMS is not engaged (engaged is the default with most kernel configurations).

What is the native/preferred mode of your display, 1024x768, or something higher? What is your GPU model, and how old is it?

czezz · 06-02-2020, 04:52 AM

Hi,
Thanks for reply.

My preferences for resolution is 1024x768.
To go higher I would need Guest Additions which im having a hard time to install.

GPU/VGA is the one provided by Oracle in VirtualBox:

Code:

00:02.0 VGA compatible controller: InnoTek Systemberatung GmbH VirtualBox Graphics Adapter (prog-if 00 [VGA controller])
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0
	Interrupt: pin A routed to IRQ 11
	Region 0: Memory at e0000000 (32-bit, prefetchable) [size=16M]
	Expansion ROM at <unassigned> [disabled]

My worry is what does this error really means and how to get rid of it?

Code:

xrandr: Failed to get size of gamma for output default

mrmazda · 06-03-2020, 11:00 PM

Quote:

Originally Posted by czezz

My worry is what does this error really means and how to get rid of it?

Code:

xrandr: Failed to get size of gamma for output default

It occurs because the in use DDX doesn't provide functionality required by xrandr to perform the requested action.