Apple Cinema Display HD only shows 1280 x 800 available...
 

I have an Apple Cinema Display HD (30") connected to a MacBook Pro via a SEWELL Minideck (USB to DVI) and the only resolution available is 1280 x 800.

Sewell Tech Support redirected me here.

I'm attaching the info from the debug tool.

It sounds like a simple detection bug, whatever code their developers have written is failing to recognize native resolutions properly...

I suspect, there is a quick fix, if only the code was open source... :)

scubadave - no it is not a detection bug and the software detects available resolutions properly. The reason why Jaime Gago sees 1280 x 800 as the only resolution available is that according to the logs, his monitor only supports 2 modes:

"Display Modes
--------------
1280x800x24@60
2560x1600x24@60"

2560x1600x24@60 is not supported by SEWELL Minideck (USB to DVI).

Regards

Can you be more precise?
Technically the monitor (Apple Cinema HD) *does* support much more than those 2 resolutions modes.
If I connect it via the Mini Display link I have many resolutions options. So why is there only 1 available when connected on the Sewell Minideck? Why are the logs reporting only those 2 modes when the display is capable of much more?

All Apple displays from the ADC ones onwards don't have an onboard scaler and thus support only the native resolution. The exception are the 30" displays that also support the one-quarter resolution that is easy to obtain without a scaler.
What happens when you connect these displays directly to your Mac is that the graphics card makes more resolutions available by performing full screen scaling. In other words, the GPU does the scaling instead of the display.
DisplayLink drivers don't have this additional full-screen scaling function (yet).
I can't give a date for this feature, it is not in high demand because usually the displays are used at their native resolution anyway. In your case of course this is not possible.

Thanks Carlo, that makes it _at last_ clear.

Same problem
 

Hi Guys,

I also just bought TWO of the newer USB to DVI adapters and was shocked when I got only 1 resolution on my 30" cinema HD:( Is there ANY workaround? Is supporting scaling on your development roadmap? Could we get a group of people together to whom this feature really matters to donate money to get this feature supported? I would participate. Can anything be done? Without this the product is useless to me:(((

Thank you.

Even if scaling were enabled on these devices, you'd still only be able to run your 30" display at 1920x1200, which would look *horrible* due to it not running at the native resolution of the screen. It would also mean that your 30" displays were a waste of money and you'd be better off with 30" IPS based TV screens with 1920x1200/1080 resolution - which would be far cheaper.

The adapters aren't dual link DVI compatible. The previews of USB3 based display link devices apparently do have support for these higher resolutions but don't expect to see them on the market any time soon - I think I saw Q1 2011 being the earliest expected due date and even then, you'd need a USB3 based computer which in the Mac world currently means only Mac Pros with a PCI Express USB3 expansion card and MacBook Pros with an ExpressCard/34 (Current 17" MBP and I think all Intel based 17" MBPs and all pre 2009 15" MBPs - all non SD card 15" basically).

Spanky you seem to be well informed!
I agree that even 1920x1200 won't look nice on the 30", especially if put side by side with another identical screen with a different pixel density.
At the moment I don't have a solution to propose, I'm sorry.

Thanks for the clarifications. I have for now just connected the 30" via Apple's adaptor, and then used the 2 displaylinks to power to 24" screens.

I do have an incredible amount of "stream number arrived to late" errors showing in the console from displaylink always after waking from sleep for quite a while which I will create a separate thread about.