Output video to overscanning TV with Intel graphics

Question

I have a television which is 1366x768 resolution.
It is a JVC LT-32EM49.

When devices are connected to it, it lists the normal resolutions such as 480p, 720p, 1080p/i. But it does not list 1366x768.

The TV removes some pixels on the edges of the screen when using 720p or higher input. TVs that overscan are supposed to offer an option to disable this, but I am very confident that this TV does not allow the user to disable the overscanning. (Devices such as the PS3 seem to expect and work around this irrational behavior by not putting anything important directly on the edges of the screen. But with computers, the edges of the screen are more important.)

Now, when a computer was connected to this TV with a Radeon HD 4350 card (via DVI-HDMI adapter), Windows XP Professional SP3 listed 1366x768 as an available resolution (and it worked perfectly). I assume this was an OS-level workaround.
This same graphics card could be made to work properly (that is, having the full screen visible) with Linux via much fiddling with XRandR and --set.

However, I now wish to attach a Dell Studio Hybrid 140G (graphics card being Intel HD graphics, the GMA X3100 specifically) to this television. (The card has DVI and HDMI outputs)
And the Intel integrated graphics cards seem to have no such option to cope with problematic televisions and their relentless overscanning.

I have Googled much on this topic, to no avail. I suspect this post will appear as on the first page of such queries in the near future. xrandr --set overscan is not available for this graphics card, and --scale and --transform (the most widely touted solutions) do not fix the problem on this television.

Dan Henderson · Answer

I feel your pain. I fought with this same issue for quite a few hours before I decided to just start plugging different values and combinations of parameters into XRandR, and suddenly I was astonished to see that one of the commands I had previously entered without success had now produced the desired result! After some further fiddling, I managed to produce a repeatable scenario, which I will share with you:

$ xrandr --output HDMI-1 --mode 1280x720 --transform 1,0,-40,0,1,-25,0,0,1 --panning 1280x720+40+20
$ xrandr --output HDMI-1 --mode 1280x720 --fb 1200x680 --transform 1,0,-40,0,1,-25,0,0,1 --panning 1280x720+40+20

These two lines are identical except that the second has the addition of the --fb 1200x680. The second line is the desired result, but it only worked when I entered it after entering the other line first - if I used the second line when coming from a "standard" configuration, I'd still have the cut-off bottom and right edges.

The -40 and -25 in the transform parameter pushes the entire picture down and to the right; the +40+20 on the end of the panning parameter adds padding to the bottom and right edges, and those numbers need to equal 1/2 of the difference between mode and fb.

(Note that my horizontal numbers are different: I needed 25 extra pixels on the left, but only 20 on the right. Regardless of your top and left margins in transform, you'll want to double your panning modifiers when determining the value for fb.)

Output video to overscanning TV with Intel graphics

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