Date: Sat, 22 Aug 2009 15:48:07 +0100 From: Bruce Cran <bruce@cran.org.uk> To: Hans Petter Selasky <hselasky@c2i.net> Cc: Alexander Best <alexbestms@math.uni-muenster.de>, freebsd-usb@freebsd.org Subject: Re: kernel debugger and usb keyboard Message-ID: <20090822154807.0cf17700@gluon.draftnet> In-Reply-To: <200908032127.32353.hselasky@c2i.net> References: <permail-20090803185516f7e55a9d00006928-a_best01@message-id.uni-muenster.de> <200908032127.32353.hselasky@c2i.net>
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On Mon, 3 Aug 2009 21:27:30 +0200 Hans Petter Selasky <hselasky@c2i.net> wrote: > On Monday 03 August 2009 20:55:16 Alexander Best wrote: > > just tried settings `sysctl debug.kdb.panic = 1`. if i use this way > > to enter the kernel debugger my usb keyboard works. if i type > > "continue" however the kernel panics and the kernel debugger gets > > yet entered again, but without the keyboard working. > > The USB controller which the keyboard is hooked onto will not work > after panic has been entered, due to some state not being cleaned up. > > To increase the chance of the keyboard working on a panic, connect > the keyboard to a separate USB controller. > > > i don't know how to produce backtraces since the keyboard doesn't > > work. > > Ok. > > > > > the other way of entering the debugger without my keyboard working > > was to simple press "ctrl+ast+esc". > > Yes, because most likely the DDB is entered directly from the USB > keyboard code, and the USB stack does not allow function recursion in > that case! USB keyboard support is now working in the debugger, but it seems the USB stack hangs up if you exit out of the debugger, if the system hasn't crashed and can keep running - the keyboard doesn't respond, and unplugging and re-plugging it doesn't help. If I press Ctrl-Alt-Esc followed by "c" to continue, the output scrolls up the window as if the Enter key is being held down. -- Bruce
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