Thanks for posting! I’m afraid I’ll just be confirming what you already know.
Unfortunately not every mode is offered on every monitor. Here’s how DisplayLink’s drivers work (on Windows 7):
The driver reads the monitor’s EDID, which returns the exact timings of the native/max mode of the monitor. This is the default/preferred mode which will be set if at all possible (it’s the 1920x1080 mode on this monitor). This mode makes maximum use of what the monitor offers.
In the EDID is also back-up lower resolution modes that the monitor offers (these are known modes that the monitor’s internal scaler can scale up to the native mode of the monitor; most monitors can actually scale up any arbitrarily lower mode, but they can only list a few). Those modes from the EDID are added to the list of options, in case the graphics adapter can’t support the highest mode, or the user wants to select a lower mode.
Windows also adds in some standard modes (640x480, 800x600, and 1024x768) with standard VESA timings.
It’s this combined set of modes which are offered to the user for any mode choices. Unfortunately, if there’s a mode you want that isn’t in any of the three sets, there’s no easy way to add it.
DisplayLink’s behavior here is more conservative than some graphics controllers. Some graphics controllers’ drivers offer a very long list of modes, using standard timings. Some may not work on the attached monitor, but the drivers offer those modes that might fail anyway, and let the user recover from any black screens or other failures. DisplayLink’s drives make the choice of not presenting modes to the user, other than what’s known to work (from the EDID), to avoid the possibility of black screens and the like.
So some thoughts:
* It would be interesting to know what factors are making 1920x1080 (the native mode of the monitor) or 1152x864 (one of the monitor’s back-up modes in the EDID), undesirable on this monitor. If it would be possible to live with either of those two modes, we’d be within what the monitors’ EDID offers.
* If running at the particular mode of 1366 x 768 is critical, and you have other monitors around, you can connect a monitor whose max is 1366x768, and the dock will automatically select that mode by default.
Hopefully this background will at least help to understand why only particular lower-res modes are offered. I’m sorry it wasn’t the news you were hoping for. Please just let us know if there’s anything we can answer to clarify or offer to help. We’ll do everything we can.
Thanks and best wishes,