From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: Re: [PATCH] mfd: tps6586x: Handle interrupts on suspend Date: Thu, 25 Oct 2018 16:01:20 +0300 Message-ID: <5a6c9c02-78b1-a30f-e938-573e89e3b92c@gmail.com> References: <1539955373-13735-1-git-send-email-jonathanh@nvidia.com> <20181022095257.GD4014@ulmo> <366ad7c3-85e2-3526-1c0b-6d2fbde4c552@gmail.com> <72b80285-d6ff-9cb9-3bcd-bb3d92006323@nvidia.com> <3e79e753-4e63-5bf0-c9ff-40547d053c8a@gmail.com> <551feb87-efb0-4bc3-2f0e-84ab55f7cbfe@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <551feb87-efb0-4bc3-2f0e-84ab55f7cbfe@nvidia.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Jon Hunter , Thierry Reding Cc: Lee Jones , linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, stable@vger.kernel.org List-Id: linux-tegra@vger.kernel.org On 10/24/18 5:19 PM, Jon Hunter wrote: > > On 24/10/2018 13:44, Dmitry Osipenko wrote: >> On 10/24/18 1:49 PM, Jon Hunter wrote: >>> >>> On 22/10/2018 12:19, Dmitry Osipenko wrote: >>>> On 10/22/18 12:52 PM, Thierry Reding wrote: >>>>> On Fri, Oct 19, 2018 at 02:22:53PM +0100, Jon Hunter wrote: >>>>>> From: Jonathan Hunter >>>>>> >>>>>> The tps6586x driver creates an irqchip that is used by its various child >>>>>> devices for managing interrupts. The tps6586x-rtc device is one of its >>>>>> children that uses the tps6586x irqchip. When using the tps6586x-rtc as >>>>>> a wake-up device from suspend, the following is seen: >>>>>> >>>>>> PM: Syncing filesystems ... done. >>>>>> Freezing user space processes ... (elapsed 0.001 seconds) done. >>>>>> OOM killer disabled. >>>>>> Freezing remaining freezable tasks ... (elapsed 0.000 seconds) done. >>>>>> Disabling non-boot CPUs ... >>>>>> Entering suspend state LP1 >>>>>> Enabling non-boot CPUs ... >>>>>> CPU1 is up >>>>>> tps6586x 3-0034: failed to read interrupt status >>>>>> tps6586x 3-0034: failed to read interrupt status >>>>>> >>>>>> The reason why the tps6586x interrupt status cannot be read is because >>>>>> the tps6586x interrupt is not masked during suspend and when the >>>>>> tps6586x-rtc interrupt occurs, to wake-up the device, the interrupt is >>>>>> seen before the i2c controller has been resumed in order to read the >>>>>> tps6586x interrupt status. >>>>>> >>>>>> The tps6586x-rtc driver sets it's interrupt as a wake-up source during >>>>>> suspend, which gets propagated to the parent tps6586x interrupt. >>>>>> However, the tps6586x-rtc driver cannot disable it's interrupt during >>>>>> suspend otherwise we would never be woken up and so the tps6586x must >>>>>> disable it's interrupt instead. >>>>>> >>>>>> Prevent the tps6586x interrupt handler from executing on exiting suspend >>>>>> before the i2c controller has been resumed by disabling the tps6586x >>>>>> interrupt on entering suspend and re-enabling it on resuming from >>>>>> suspend. >>>>>> >>>>>> Cc: stable@vger.kernel.org >>>>>> >>>>>> Signed-off-by: Jon Hunter >>>>>> --- >>>>>> drivers/mfd/tps6586x.c | 24 ++++++++++++++++++++++++ >>>>>> 1 file changed, 24 insertions(+) >>>>> >>>>> So does this mean that the SPI interrupt for the PMIC can still be a >>>>> wakeup source even if it is masked? This is slightly odd because now >>>>> you're saying that this does work while it doesn't work for the RTC >>>>> interrupt. So is this an implementation quirk of the LIC/GIC on Tegra >>>>> which doesn't extend to the TPS6586x? Or am I missing something? >>>> >>>> What is the expected behaviour of IRQ disabling? Should it disable wakeup ability or only mask IRQ handling? >>> >>> I believe only mask the interrupt. However, the caveat here could be if >>> the parent interrupt controller actually supports wake-up. For Tegra it >>> is the LIC that handles the wake-up. >>> >>>> Couple months ago disabling of IRQ was disabling the wakeup, now something has been changed in kernel and wakeup isn't getting disabled. So either there was a bug before that was fixed or there is a bug now. >>> >>> Are you sure you were disabling the PMIC host interrupt? If you disable >>> the RTC interrupt in the PMIC's RTC driver, then this will prevent the >>> wake-up from occurring because you are masking the interrupt within the >>> PMIC and so it will never generate an interrupt to the host. >> >> I'm pretty sure (but not 100%) that was trying the same change as in your patch and it didn't work sometime before. If disable_irq() shouldn't disable wakeup, then everything is perfect now. > > Please note that this is very similar to the following fix where I > experienced the same problem with another PMIC a couple years back ... > > 35deff7eb212 ("mfd: as3722: Handle interrupts on suspend") > > I did not bother setting the enable/disable_irq_wake() for the tps6586x > host irq during resume/suspend because the irqchip for the tps6586x has > an irq_set_wake function that propagates the wake enable/disable. Okay, thanks.