External HDMI monitor blinking after upgrade to 16.04

Question

I'm getting many issues after upgrade to 16.04 in my Dell 15R 5537. Today I was unable to watch movies as I used to do with 15.10 in my Sony 42' TV with resolution of 1290x1080 using HDMI cable.

Now as soon as I move to the external display the tv starts to blink. :(

I tried to lower the tv resolution to 1280x720. It worked only when both displays are active. When I set the mode where only the tv is active it also blinks.

Another way to make the tv stop to blink was selecting the mirror mode.

lspci | grep VGA :

00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09)
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Venus PRO [Radeon HD 8850M / R9 M265X] (rev ff)

xrandr -q

Screen 0: minimum 8 x 8, current 1366 x 768, maximum 32767 x 32767
eDP1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 194mm
   1366x768      60.04*+  40.05  
   1360x768      59.80    59.96  
   1280x720      60.00  
   1024x768      60.00  
   1024x576      60.00  
   960x540       60.00  
   800x600       60.32    56.25  
   864x486       60.00  
   640x480       59.94  
   720x405       60.00  
   680x384       60.00  
   640x360       60.00  
DP1 disconnected (normal left inverted right x axis y axis)
HDMI1 connected (normal left inverted right x axis y axis)
   1920x1080     60.00 +  50.00    59.94    30.00    24.00    29.97    23.98  
   1920x1080i    60.00    50.00    59.94  
   1280x1024     60.02  
   1280x720      60.00    50.00    30.00    59.94    29.97    24.00    23.98  
   1024x768      60.00  
   800x600       60.32  
   720x576       50.00  
   720x576i      50.00  
   720x480       60.00    59.94  
   720x480i      60.00    59.94  
   640x480       60.00    59.94  

could someone give a clue what is going on?

thanks

Solution

Don't know what was changed in version 16.04, but I found that the blink is cause by an unsupported resolution.

I found that setting resolution/rate values using randxr is not doing any effect. Don't know the reason.

What I had to do was change resolution and rate values in the ~/.config/monitors.xml file and then restart the machine.

After that I was able to watch my movies in my tv again.

Thanks to @fakedad !!!

Comments

[fakedad]

Can you post the output of xrandr -q?

[Cristiano]

@fakedad. Hi, I edit and added what you have requested.

[fakedad]

Have you tried adjusting the refresh rate?

[Cristiano]

@fakedad. no, but I will. do you suggest any value?

[Cristiano]

I tried this: xrandr --output HDMI1 -s 1920x1080 -r 50 but I can't see the '+' or '*' to change. Am I doing it right?

[fakedad]

I would see what the maximum supported refresh rate for the TV you're using is by looking at the specs online. Many older TVs (and, I imagine, some newer ones) don't support very high refresh rates. Also, you may want to try lower resolutions, like 1280x720 (as you mentioned earlier) in addition to lower refresh rates.

[Cristiano]

But what I'm not understanding is that this have been working since version 14.04. I never need to use xrandr before. Is the command that I'm using right?

[fakedad]

Let us continue this discussion in chat.

[o.v]

Xfce configuration file location: ~/.config/xfce4/xfconf/xfce-perchannel-xml/displays.xml