Display frequency not supported


#1

Hello I have a problem. I have a Raspberry Pi 3B and an old monitor with VGA and I used an adapter from HDMI to VGA. Other operating systems works with it, but ubuntu mate not. I have to connect it to my TV and it works. If I connect it to the TV and than to my monitor without switching off the Raspberry, my display takes the error message “Frequency not supportet”. Can someone help me?


#2

Can you find what the frequency is being used when the other OS work? (preferably as Horiz and vert resolutions).
If you know these, and can get to the content of the boot partition to modify config.txt, you can set these parameters.
BTW you haven’t said which version is giving trouble.


#3

ubuntu mate 16.04.2
Under Raspbian 1280x1024 60Hz. In what line I must edit it?


#4

this is basic info - look at the basic video stuff, and then follow the link to Video/display.
HTH
Derek


#5

Thanks but it doesn’t work to change the frequency


#6

We don’t yet know the chracteristics that the combined adapter and TV support, but you could try
hdmi_group =2
hdmi_mode=35

If this fails, report the output of:
tvservice -s
under Raspbian


#7

I have changed the lines what you write but it doesn’t work.
Terminal:
[email protected]:~ $ tvservice - s
state 0x12000a [HDMI DMT (35) RGB full 5:4], 1280x1024 @ 60.00Hz, progressive


#8

If yu are proceeding as in your original post (TV connected to Raspbian, and then reconnect it to UbMate 1604) then the RPi will be in the wrong state and this won’t get corrected. If, however, you’ve modified the UBmate config.txt, and are booting with the TV connected and switched on there is a different scenario to fix.
You may have to take account of a connection weakness with the HDMI-VGA converter by telling the UBMate system to assume it has HDMI connected (in addition to describing the mode to use)
hdmi_force_hotplug=1
in config.txt,
AND you may need to force the system to ignore the state reported by the TV/adapter and use an EDID data file.
I suggest you try booting with the TV connected and the additional line above - if this doesn’t get ther we can get to obtaining the EDID file and telling the system to use it.
HTH
Derek