[Libdlo] Linux DispayLink issues

Martin Decky martin at decky.cz
Tue Mar 15 02:35:10 PDT 2011


Hello folks,

> 1. It have not real plug and play support, and when I disconnect device
> from USB and then reconnect it, it is not working (X server driver
> cannot restart it). This limitation make it hard to implement (and not
> useful) for wireless USB case.
> 2. It is working only in GNOME failsafe desktop mode.
> 3. It is working only in multi screen mode and not as external monitor
> (Xinerama off).

I am not quite sure if I fully understand the reasons for these problems 
or the exact use cases you want to achieve (perhaps it might be helpful 
to describe your use cases explicitly in detail).

However, I'd bet that the root cause of these problems is still the 
same: The current architecture of X.Org X11 Server does not allow to 
load and unload graphics drivers dynamically or do any essential 
reconfiguration of the X server while it is running.

Certainly, we have the XRandR extension which can manage dynamically 
attached displays connected to a single GPU, but you cannot force the X 
server to load dynamically a new graphics driver, create dynamically a 
new display for it or add the new graphics device as a new screen into 
an existing xinerama-enabled display. You can run new instances of the X 
server and this approach can be used to "emulate" some of the features, 
but I still consider it a poor man's solution.

As I see it, these are fundamental issues of the current X.Org X11 
Server implementation (or in some cases even issues of the X11 protocol 
design).


Best regards

Martin Decky


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