From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Stern Subject: Re: [RFC][PATCH 2/2] PM: Rework handling of interrupts during suspend-resume Date: Thu, 26 Feb 2009 22:20:27 -0500 (EST) Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Linus Torvalds Cc: Jeremy Fitzhardinge , LKML , Jesse Barnes , "Eric W. Biederman" , pm list , Thomas Gleixner , Ingo Molnar List-Id: linux-pm@vger.kernel.org On Thu, 26 Feb 2009, Linus Torvalds wrote: > The _only_ driver that does enable_irq_wake() on x86 is the cmos timer > driver, and even there it actually doesn't use irq_wake, but ACPI. Why? > Because I don't think irq wakeup even _works_ on x86. > > So the whole enable_irq_wake is largely some embedded ARM platform issue, > and a very special case, and doesn't exist anywhere else. > > Maybe I'm missing something, but it's definitely not the normal case. What you're missing is that the embedded world is quite a large one. As any member of CELF will tell you, there are lots more embedded systems around than there are desktop/laptop computers. (I admit, I don't know what the ratio is if you restrict your attention to systems running Linux.) We can't afford to regard them as second-class citizens. Plenty of embedded systems use normal interrupts from GPIO lines as wakeup sources. Don't discount the need for this just because desktop systems don't use them that way. It may not be "normal" in the circles you're accustomed to, but it _is_ normal elsewhere. Alan Stern