On Sunday 18 December 2011 11:58:57 Andriy Gapon wrote: > 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.
mtx_assert(&Giant, MTX_OWNED); will panic if Giant is not locked. Do you need an example? > > > 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! I will have a look at it when I find some time! --HPS _______________________________________________ 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"
