Hi Poppy, A year onward, I am experiencing near identical troubles and problems with the Beaglebone on a generic LCD panel. I am following similar steps but i get the "No protocol specified. Cannot open display :0.0". Do you recall what fixed this for you?
Thanks for any help in advance! Best, Venky On Wednesday, August 2, 2017 at 4:47:36 PM UTC+5:30, Poppy Miller wrote: > > Hi, > > I am using the latest MachineKit (downloaded from > http://elinux.org/Beagleboard:BeagleBoneBlack_Debian#BBW.2FBBB_.28All_Revs.29_Machinekit) > > image and am trying to change the hdmi resolution to use it with a generic > 5 inch lcd screen. The resolution I require is 800x480. > > What I have tried: > > - xrandr: I tried following the instructions on the main beaglebone page ( > http://elinux.org/Beagleboard:BeagleBoneBlack_HDMI#Forcing_A_Resolution) > > Open terminal > Type export XAUTHORITY=`ls /var/run/gdm/auth-for-root-*/database` and hit > enter. > Type export DISPLAY=:0.0 and hit enter. > Type xrandr --output HDMI-0 --mode 800x480 --rate 60. You can substitute > different resolutions and refresh rates if you like. Hit enter. > > This method gives an error "No protocol specified. Can't open display :0.0" > > I have tried other lcd names such as "default" and "HDMI-0" > > - modifying uEnv.txt: I tried adding " > kms_force_mode=video=HDMI-A-1:800x480M@60" to the uEnv.txt file (in both > /boot and /media/machinekit/boot) as suggested at > http://blog.machinekit.io/2013/07/custom-hdmi-resolution.html. I tried > changing the name of the screen from "HDMI-A-1" to "HDMI-0" and "default". > > This gives no errors, but also seems to have no effect on the resolution. > > > I am doing this on a tv screen which may not support the resolution I am > trying to change it to. This is because I cannot see enough of the screen > on the lcd at the wrong resolution to open the terminal and modify things- > could this be causing a problem? Should I be changing the settings via > putty instead? > > Thank you in advance, > > Cheers, > Poppy > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/9675247c-83ea-45ed-9863-73101ed0d28e%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
