From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs Date: Sat, 30 May 2009 01:35:05 +0200 Message-ID: <200905300135.07103.rjw@sisk.pl> References: <1241483224-7113-1-git-send-email-khilman@deeprootsystems.com> <200905232214.57186.rjw@sisk.pl> <4A1A4297.50809@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4A1A4297.50809@samsung.com> Content-Disposition: inline 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: Kim Kyuwon Cc: linux-kernel@vger.kernel.org, Kyungmin Park , linux-pm@lists.linux-foundation.org, Andrew Morton , Linus Torvalds , Ingo Molnar List-Id: linux-pm@vger.kernel.org On Monday 25 May 2009, Kim Kyuwon wrote: > Rafael J. Wysocki wrote: > > On Saturday 23 May 2009, Kim Kyuwon wrote: > >> On Sat, May 23, 2009 at 7:29 AM, Rafael J. Wysocki wrote: > >>> On Saturday 23 May 2009, Kim Kyuwon wrote: > > [--snip--] > >>>> You changed the really important part of Linux, which may affect most > >>>> processor architectures. I think you should be careful. If some of > >>>> architectures can't take care of it (they can implement > >>>> disable_irq_wake correctly in H/W level, will you revert your changes? > >>> No, the changes are not going to be reverted. In fact things should have been > >>> done like this already much earlier. > >>> > >>> Now, do you have any particular example of a problem related to these changes > >>> or is it only a theoretical issue? > >> I'd CCing you when I'm sending a mail for this particular example of a example. > >> http://markmail.org/thread/fvt7d62arofon5xx > > > > Well, as I said above, reverting the changes that introduced > > [suspend|resume]_device_irqs() is not an option, becuase it was the only sane > > way to achieve the goal they were added for. So, we need to fix the wake-up > > problem on your platform with the assumption that > > [suspend|resume]_device_irqs() are going to stay. > > > > For starters, would it be possible to teach the 'disable' hook of your > > platform's interrupt controller not to mask the IRQs that have both > > IRQ_WAKEUP and IRQ_SUSPENDED set? That apparently would work around the > > wake-up interrupts problem. > > Thank you for considering this issue and spending your time. In order to > make your idea work, we need to add a dummy 'set_wake' hook which > returns always zero. Anyway, IMO, I think your idea is good to work > around this problem. But Kevin Hilman(OMAP PM Maintainer) would make > final decision. > > Buy the way, how can you handle the problem that a few interrupt are > discarded in a small window? I can be sure they are discarded, because I > have debugged defects which generate in sleep/resume state hundreds of > times on ARM Processors(PXA310, S3C6410, OMAP3430). Wake-up interrupts > are generated as soon as arch_suspend_enable_irqs() invoked. Sorry for the delayed response. If the wake-up interrupts are not masked, they will be delivered to the drivers as soon as arch_suspend_enable_irqs() has run. So, if the drivers are able to handle them at this point (ie. before resume_device_irqs() is called), they won't be lost. The only problem I see is that the drivers may expect their ->resume_noirq() callbacks to be executed first. Thanks, Rafael