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 drives. > 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 this context. I have written a small article about my analysis of locking in syscons, underlying kbd drivers and ukbd in particular: http://wiki.freebsd.org/AvgSyscons I could have misunderstood or missed things, so I will appreciate a review and discussion of my observations. Thank you! -- Andriy Gapon _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
