forcing lower refresh rate?

[Lennart Sorensen]

On Sat, Aug 24, 2013 at 12:09:03PM -0400, D. Hugh Redelmeier wrote:
> The Seiki monitor with "4k" resolution is inexpensive.  But it can
> only refresh a full resolution signal at 30Hz.
> 
> I want to see whether a 30Hz desktop is OK.  So I'd like to try 30Hz
> with a current monitor.
> 
> The Xorg.0.log says "Ranges: V min: 56 V max: 76 Hz, H min: 30 H max:
> 81 kHz, PixClock max 175 MHz".  This is from the monitors EDID data.
> But it can take an analog TV signal, surely at 60i and maybe 30p.
> I don't want to use analog for this test: too yucky resolution (even
> VGA isn't as clean as DVI).

Analog is handled through in internal scaler, which also takes care of the refresh rate.

It is telling you that it will only accept refresh rates of 56 to 76Hz.
So 30 isn't an option.

> Is there a way to force X to ignore EDID data on DVI?  Would 30Hz DVI
> likely work with the monitor?

In this case no.

> Oh: is 30Hz unpleasant for desktop use?  The Seiki screen itself
> refresses at 60 or 120Hz, but the image can only be changed at 30Hz.
> I assume that 60i might be possible but not be better for the viewer
> than 30p.

No idea if it would be unpleasant.  Certainly LCD screens don't have the
flicker issue that lower refresh rates caused on CRTs, so really the only
thing should be more sluggish reponse to input and changes on the screen.

-- 
Len Sorensen
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