[Libdlo] Equivalent for $DISPLAY

[Bernie Thompson]

Hi Phil,

Did I say days?  I meant 2+ weeks ...

Your patch is now in the libdlo tree
http://cgit.freedesktop.org/libdlo/commit/?id=1c47e4dbe05ea5b2a153b1c584a6ac23b50d7218

Thanks for submitting this and thinking about a standard way of
allowing user choice of DIsplayLink device to flow through the library
to applications. Note that dlo_claim_first_device() was kept in a
later change, and generally this area will almost certainly need to
evolve yet before the next library release, for a few reasons:

* The rise in importance of Roberto's kernel framebuffer driver - this
is likely to be the #1 thing any user-mode library needs to coordinate
with (just to mention that between framebuffers themselves, the
corresponding mechanism is the FRAMEBUFFER environment variable ..
e.g. FRAMEBUFFER=/dev/fb0).
* The desire to have both ends of the spectrum for APIs: one path that
"always works" from the programmer and user perspective, so they
always see something on some screen -- even if it takes over the wrong
screen.  And a second path for production apps which provides proper
control to direct things to the right screens in a multi-device,
multi-app environment (and probably an optional fallback to force
display wherever it can).
* In theory, the DisplayLink serial number isn't actually sufficient
to uniquely identify a device -- need combination of USB PID and
serial #

So any further suggestions or patches in this area to make this all
nice-as-possible are welcome.

Thanks,
Bernie


On Tue, May 26, 2009 at 10:26 AM, Bernie
Thompson<bernie at berniethompson.com> wrote:
> It may take a few days to get to it, but I'd like to take Phil's
> patch. It will mean find_first_device will disappear in favor of
> claim_first_device.  If anyone has any counter-feedback (e.g. that
> it'd be better to keep names same and just change implementation
> underneath; or on the details of DLODISPLAY), please speak up shortly.
>
> Thanks again for this patch, Phil!
>
> Thanks,
> Bernie
>