LCD resolution output does the A2109 use?

ardentblue

Junior Member
Mar 20, 2013
61
2
I'd like to hook my A2109 up to my ViewSonic VX1945WM. The monitor only goes up to 1440x900, which obviously is not enough for 1080p.

Will the A2109 query the EDID of the monitor to establish the best supported mode?

Edit- the app "LCD Resolution" Wemob Labs, works on rooted devices... but the video only shows it changing the tablet screen resolution. Unknown if it changes the HDMI output at this time.
 
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drcrash

Member
Mar 8, 2013
12
3
On my unrooted a2109 running stock JB 4.1, I have not found any way to control the HDMI output resolution into normal LCD computer monitors.

I have three native 900-line monitors (two 1600 x 900 and one 1440 x 900) and on all of them the HDMI output defaults to 640 by 480, displays at the wrong aspect ratio---stretched to fill the screen horizontally but not vertically---and looks terrible. (All of them have DVI inputs, and I use an HDMI to DVI adapter.)

My impression is that some earlier versions of Android had Settings for HDMI output resolution; I don't know why they'd have gone away.

I've seen suggestions that going through DVI may be a problem, with HDMI hardware inputs okay, but I don't know if that's true. I'm wondering if the problem is not supporting 1080p or 720p video modes. (None of my monitors lists those as discrete options, though at least one seems to be able to multiscan and figure out whatever's coming in. Unfortunately, I can't force 720p output from the a2109 and see if the monitor then handles it; it just defaults to 640 and that's that. I don't know if it picks 480p because that's the lowest "TV" resolution my plug-and-play monitors identify themselves as supporting, or if it can't identify the display modes at all and just defaults to 480p because almost any monitor can handle that.)

The biggest single reason I went with the a2109 was the HDMI output, but it turns out to be useless to me. :-(
 

drcrash

Member
Mar 8, 2013
12
3
By the way, my understanding is that if you do have root, you can change the output resolution with

setprop persist.tegra.dpy5.mode.height=<lines>
setprop persist.tegra.dpy5.mode.width=<pixels per line>

but there's a trick to it, which you should google up, because of weirdness of the build process.

(IIRC, you want those lines in build.prop, but it gets overwritten, so you have to work around that, and I don't trust myself to remember any details.)
 
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