[rescue] 1920x1080 on LCD with a TGX+ :-) (was: Re: FB resolution in PROM)

Maciej W. Rozycki macro at linux-mips.org
Sat Feb 27 19:23:12 CST 2016

On Sat, 27 Feb 2016, Andrew Jones wrote:

> > I didn't get all that I wanted - the LCDs won't sync properly to many
> > signals, and only display partial resolutions of others (such as 1920x1200
> > displayed as 1600x1200 by a SyncMaster T260). Perhaps the LCDs aren't
> > comfortable with the composite sync.
> This may not be a sign that your settings are wrong.
> I've been having this problem with an 'ifb' device.  1920x1200 is supposedly a
> supported resolution, but my only ostensibly-compatible monitor detects it as
> 4:3, and squashes everything.

 Assuming that you're using analogue video signalling maybe all you need 
to do is going into the monitor's advanced settings menu (if it has one; 
you might need to reach for a service manual) and adjusting the resolution 
recognised manually?  Perhaps it's picking the wrong one, from a set of 
predefined settings?  What resolution does the monitor report when you hit 
the wrong rendering?

 I had this issue with an LCD panel incorrectly recognising the text mode 
I'm used to, which is 80x37 characters or 720x592 pixels.  As you can 
imagine this was "approximated" as the somewhat more common 800x600 SVGA 

 So I had to go into the advanced settings menu, only available by keeping 
one of the monitor's control buttons depressed while powering the device 
on and not documented with the enclosed hardcopy manual.  There I could 
set the horizontal and vertical pixel counts as required individually, and 
once they have been both adjusted, to 720 and 592 respectively, the issue 
is gone.

 This panel is happy with sync-on-green BTW and supports monochrome input 
too, i.e. it shows shades of grey rather than green.  Configuring the 
monochrome mode is also only available via the advanced menu though (sync 
is automatic of course).  I haven't tried composite sync however as I have 
no suitable graphics device available.  The manual claims it's supported.



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