On 03/20/18 11:49, Xianwen Chen wrote: > Dear OpenBSD users, > > I run OpenBSD 6.2 amd64 on a Dell Latitude E6540 laptop. > > I hook a Dell U2412M monitor to the laptop using VGA port. xrandr > recognizes the maximum resolution of the external monitor, but the > refresh rate is slightly below 60:
> VGA-1 connected (normal left inverted right x axis y axis) > 1920x1200 59.95 + ... > I can visibly see the flickering of the screen on the external monitor. > Is this because the refresh rate is below 60? no. And I'm stopping your message here, as you are barking up the wrong tree. For 60hz, 59.95 is more than "close enough". Plus, LCD monitors are NOT like CRTs in refresh. CRTs draw one scan line at a time, that scan line and a few above it are lit up at any moment, so the entire screen flashes at the refresh rate. 60hz is about the minimum that is tolerable for most people, and many people can "feel" (if not exactly see) the difference for significantly faster refresh rates (and the faster, the better) LCDs have a much more static picture. The screen refresh rate will matter for how smooth motion can appear, but the screen itself does NOT flicker. Prove this to yourself by holding your hand out, fingers spread, and waving it back and forth rapidly in front of a CRT (if you can find one) and an LCD monitor. You will see very different results. Most likely what you are seeing is your monitor having a bad time with the timing of the computer. I suspect the "Auto-adjust" button will do wonders, but I have also found that some computers just put out garbage to the analog video port. And in one case, I found that having both the VGA and HDMI cable attached to the monitor, even though only the VGA was attached to the computer, caused annoying flicker on the monitor that mostly went away when I happened to need that HDMI cable elsewhere. Nick.
