From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: Re: Wait for console to become available, v3.2 Date: Tue, 21 Apr 2009 00:13:48 -0700 Message-ID: <200904210013.48551.david-b@pacbell.net> References: <20090420234006.GA1958@cuplxvomd02.corp.sa.net> <20090421064346.GB8020@elte.hu> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090421064346.GB8020-X9Un+BFzKDI@public.gmane.org> Content-Disposition: inline Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Ingo Molnar Cc: David VomLehn , Arjan van de Ven , "H. Peter Anvin" , Thomas Gleixner , Linus Torvalds , Linux Kernel Mailing List , Linux USB Mailing List , Linux Embedded Mailing List , Andrew Morton On Monday 20 April 2009, Ingo Molnar wrote: > The proper approach would be to use one of the async_synchronize*() > facilities in kernel/async.c to properly order the opening of the > console with device init. Stepping back a moment from "how" to make sure "what" is agreed on. I think I see three scenarios here: - Classic PC or server, where there's a meaningful console; - Deeply embedded systems, where there isn't; - Development stages of "deeply embedded", where there *may* be one. If that's correct, then async_synchronize() isn't a full answer... I think a fair number of cases can be papered over with a serial console with no hardware flow control, which isn't hooked up to anything. Maybe the board needs a test/development jig to get one; without it, the "console" bits spill out into the aether. Linux can dump bits to ttyS0, which will act like /dev/null. But the problem case here seems to be one where such un-hooked-up serial ports are not realistic options. Which is why the regression in USB console functionality has been troublesome. Is that correct? - Dave -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html