From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH 0/4] Fastboot revisited: Asynchronous function calls Date: Sun, 4 Jan 2009 11:11:53 -0800 (PST) Message-ID: References: <20090104092430.7ffd2c41@infradead.org> <20090104103104.6fdda9f2@infradead.org> <20090104110559.306186c4@infradead.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: In-Reply-To: <20090104110559.306186c4@infradead.org> Sender: linux-acpi-owner@vger.kernel.org To: Arjan van de Ven Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, fweisbec@gmail.com, linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org, linux-acpi@vger.kernel.org, akpm@linux-foundation.org List-Id: linux-ide@vger.kernel.org On Sun, 4 Jan 2009, Arjan van de Ven wrote: > > or we declare the irq probing stuff "rare" and just make THAT fully > serializing.... > do a full synchronization before starting a probe Yes. That's entirely possible. However, have you verified that if an async thread does a synchronization, it doesn't deadlock? > > That said, I also wonder if we really even need to autoprobe the > > interrupts on any modern hardware. Rather than trying to speed up irq > > probing, maybe we could figure it out some other way.. The only thing > > that matters on 99% of all machines are the one or two standard ports > > that normally show up on 2f8h/irq3 and 3f8h/irq4 or something like > > that. > > too bad this stuff isn't PCI enumerated. > but if someone really still maintains this code, it could probably be > rewritten in a "we think it's likely irq 3. how about we test that. Oh > no? then we do expensive probing" kind of way. > > Right now I don't think I have time for it (this is going to take time.. > there's so many weird things with serial ports that it's bound to break > stuff in the beginning etc) Yeah. The problem is that that driver is used on such varied hardware. But we can probably pick it up from PnP/ACPI, and autoprobe only for things that don't get the info from there (either because they are not PC's, or becuase PnP/ACPI isn't configured in). This is one case where I wouldn't be afraid of PnP information, because we could easily choose to only trust it if it makes sense (ie "if it's the standard 2f8/irq3 thing, then you might as well trust PnP"). Linus