on 17/12/2011 19:06 Hans Petter Selasky said the following:
> If the problem is only in UKBD driver, I don't think this is a big problem to
> solve. The reason for the auto-magic locking, is that I've sometimes seen
> callers in non-polling mode call into UKBD without Giant locked. And this
> causes a panic when starting USB transfers, because the code expects Giant to
> be locked.
Hmm, do you have an example of such a panic? I couldn't find how this could be
possible in my examination of non-polling entry points into syscons and kbd
> Requirement: I would say that to use UKBD polling mode, the scheduler must be
> stopped. Else you should not use polling mode at all. I think that mountroot
> is getting characters the wrong way in this regard.
I think that this is a too strong / unnecessary requirement. I think that now
(after my recent syscons commits) ukbd should work correctly and optimally in
I have written a small article about my analysis of locking in syscons,
underlying kbd drivers and ukbd in particular:
I could have misunderstood or missed things, so I will appreciate a review and
discussion of my observations. Thank you!
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