Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752900Ab3GAH55 (ORCPT ); Mon, 1 Jul 2013 03:57:57 -0400 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:33580 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752678Ab3GAH54 (ORCPT ); Mon, 1 Jul 2013 03:57:56 -0400 Date: Mon, 1 Jul 2013 17:48:22 +1000 (EST) From: Finn Thain To: Brad Boyer cc: Geert Uytterhoeven , linux-m68k@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] m68k/mac: Allocate IOP message pool and queues dynamically In-Reply-To: <20130701065258.GA8425@cynthia.pants.nu> Message-ID: References: <1372586542-1318-1-git-send-email-geert@linux-m68k.org> <20130701065258.GA8425@cynthia.pants.nu> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1664 Lines: 43 On Sun, 30 Jun 2013, Brad Boyer wrote: > On Sun, Jun 30, 2013 at 12:02:22PM +0200, Geert Uytterhoeven wrote: > > > > if (iop_scc_present) { > > printk("IOP: detected SCC IOP at %p\n", iop_base[IOP_NUM_SCC]); > > + alloc_msg_queue(IOP_NUM_SCC); > > Technically, this isn't actually useful. As long as we never start this > IOP, it can't ever send or be sent any messages. That assumes that the SCC IOP is in a stopped state after iop_preinit(). But I don't think that's the case. If it is technically possible to exchange messages with a device in bypass mode (?) then I think the code above is correct. > > @@ -315,6 +307,9 @@ void __init iop_register_interrupts(void) > > } else { > > printk("IOP: the ISM IOP seems to be alive.\n"); > > } > > The if/else above isn't useful if it is run before the call to > iop_start. However, it's also useless if it is called immediately after > the call to iop_alive which is now below. It was supposed to eventually > be called in the background on a regular schedule, but that never > happened. > I agree. That if/else statement and the conditional printk's should be omitted. I had thought that in the existing code the interrupt service routine was registered before the call to iop_start() but in fact iop_start() happens first. Looks like a bug to me. The interrupt handler needs to be able to acknowledge unsolicited messages... Finn -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/