[Intel-gfx] [RFC] VGA hotplug support for i915 kms

[Eric Anholt]

On Fri, 2009-01-16 at 14:42 +0100, Jakob Bornecrantz wrote:
> Jesse Barnes wrote:
> > On Wednesday, January 14, 2009 2:14 pm Jesse Barnes wrote:
> >> Here's a work in progress VGA hotplug patch that I've been testing on my
> >> GM45.  I've only tested VGA interrupts so far, but other ports may work or
> >> should be easy to enable.  When a hotplug interrupt is received, the i915
> >> interrupt handler kicks off a work queue which ends up sending a uevent.
> >> I've deliberately done nothing else; I figure userspace should decide what
> >> to do with the event (ignore it, probe outputs, set up a cloned or extended
> >> configuration, etc.).
> >>
> >> Thoughts or comments?  The passing of the DRM device struct to the work
> >> function is pretty ugly at this point, and could be improved, and whether
> >> hotplug detection is enabled should probably be configurable since it
> >> depends on the outputs being powered enough to detect events.
> > 
> > Here's a slightly less revolting version.  I removed all the global variables,
> > and moved to using the system wide work queue rather than an i915 specific one,
> > so things are much cleaner & clearer.
> > 
> > Comments?  Userspace will still need to call getresources after receiving a
> > hotplug event, but I think that's better than trying to do something by default
> > in the kernel.
> 
> When we only run fbcon we might not be blessed with a clever userspace 
> that can add a new monitor to the fb config. Maybe we should run some 
> sort of detection code in the intel fb code.

Our experience with trying to "do something sensible when we notice new
things plugged in" in the early randr 1.2 days was that it was a
terrible idea that made users hate us.  I suspect it would be even worse
if we tried it in the kernel.

-- 
Eric Anholt
eric at anholt.net                         eric.anholt at intel.com


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