On 09/07/2011 04:27 PM, Colin Guthrie wrote:
'Twas brillig, and David Henningsson at 07/09/11 14:37 did gyre and gimble:
The idea of "start to use what you plug in" is nice. If you plug
something in, you likely want to use it. Or do you? Anyway, that
approach seems to me to have an unsolvable problem: We don't know that
it actually was plugged in.
I've tried to talk to a few people, and from what I can tell, there is
no point in time when the system can be considered to be fully "up and
running". This means e g, if a new bluetooth device shows up say 30
seconds after PulseAudio starts, we don't know if this was because
someone actually connected the bluetooth headset at that point, or if it
was connected from start but took 30 seconds to respond and negotiate
with the bluez stack. Same goes for USB, and in theory other devices as
well, but I've never seen it happen in practice to anything internal/PCI.
Also, this applies not only at boot, but also at resume from suspend or
hibernate.
Given that lack of information from the kernel/hardware, I can only
assume that order-based handling is bound to fail. And so is
module-switch-on-connect, that implements this. (And so is Ubuntu's
suspend/resume script, btw.)
Yay, I never did like that script :p
Probably stupid to mention it here as it risks the conversation going
off-topic, but anyway, the day PulseAudio upstream offers an alternative
solution I don't think anybody would mind removing it.
This leaves us rule/priority-based policy decisions, which I believe is
what Colin thinks as well. Comments?
Yup, but you outlined it nicely :)
That said, there is likely still scope for changing where in the
priority list new devices are injected (top or bottom being the only two
valid choices),
Hrm. I think we have to do a little bit more clever than that. I'd like
some kind of base priority for a device that is used given that the user
never configures anything, based on form factor and other things. Then
exactly how a new device would interact with a priority list that user
has messed around with, might require some thought to get intuitive.
although that will still be subject to the problems you
outline above. Hopefully the general use case is more "hotplug" related
than "first boot", so I'm not sure there will be overly many practical
problems, but you're absolutely right to consider them.
Having things working as expected out-of-the-box should not be
underrated. First impressions last and might save me quite a few
unnecessary bug reports as well. So IMO we need to solve both.
--
David Henningsson, Canonical Ltd.
http://launchpad.net/~diwic
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