rotating a display

[djh]

On Mon, 23 Dec 2019 18:24:16 -0500
Eric Sokolowsky <esok127 at gmail.com> wrote:

>You can use the old style of options to rotate the screen:
>
>DISPLAY=:0 xrandr -o left

Thanks for the suggestion. I had explained in my original message how
xrandr didn't work and that was why I was looking for help.

It turned out that the problem was specific to the pi. It has two
possible video drivers apparently and the default one does not support
xrandr. I have no idea why not, nor why there are two drivers and one
is apparently broken, but after switching to the other driver,
everything now works.

>On Fri, Dec 20, 2019 at 7:51 AM djh <xorg at howorth.org.uk> wrote:
>
>> I've just attached a display to a Pi 3B+. It's an old display
>> attached through a VGA-HDMI converter (no idea whether that's
>> relevant!). I've also attached a USB keyboard, though not yet a
>> mouse.
>>
>> I want to run the display in portrait mode. When I booted it came up
>> sideways (in landscape mode) as I expected. I started trying to use
>> xrandr via ssh to configure the display but haven't figured out how
>> to get it to work. Here's a sample of some output:
>>
>> $ xrandr -display :0 --prop
>> xrandr: Failed to get size of gamma for output default
>> Screen 0: minimum 1280 x 1024, current 1280 x 1024, maximum 1280 x
>> 1024 default connected 1280x1024+0+0 0mm x 0mm
>>         non-desktop: 0
>>                 supported: 0, 1
>>    1280x1024      0.00*
>> $ xrandr -display :0 --output 'default' --rotate left
>> xrandr: output default cannot use rotation "left" reflection "none"
>>
>>  I searched but haven't found any articles that explain my problem.
>> So I thought I'd try lxrandr instead. That pops up a dialog box on
>> screen saying "Unable to get monitor information!" and prints an
>> error on the command line:
>>
>> $ lxrandr --display :0
>> Can't open display
>>
>> Somebody then told me how to rotate it 'the pi way', by
>> editing /boot/config.txt  That worked, but I'd like to understand why
>> the X way doesn't. I'm also unable to access the display remotely.
>> From my ssh session on the pi I can launch xeyes for example:
>>
>> $ DISPLAY=:0 xeyes
>> ^C  # terminate from keyboard
>>
>> and I turned off access control:
>>
>> $ DISPLAY=:0 xhost +
>> access control disabled, clients can connect from any host
>>
>> But I can't connect to the pi from another host:
>>
>> $ DISPLAY=RpiBplus:0 xeyes
>> Error: Can't open display: RpiBplus:0
>> $ ping RpiBplus
>> PING RpiBplus.fritz.box (192.168.1.22) 56(84) bytes of data.
>> 64 bytes from RpiBplus.fritz.box (192.168.1.22): icmp_seq=1 ttl=64
>> time=0.314 ms
>> $ DISPLAY=192.168.1.22:0 xeyes
>> Error: Can't open display: 192.168.1.22:0
>>
>> I'd appreciate any suggestion for places to look to explain this
>> mystery to me, or actual solutions of course :)
>>
>> Thanks, Dave