28.04.2020 11:02, Jon Hunter пишет: > > On 27/04/2020 16:38, Dmitry Osipenko wrote: >> 27.04.2020 17:45, Dmitry Osipenko пишет: >>> 27.04.2020 17:13, Dmitry Osipenko пишет: >>>> 27.04.2020 15:46, Dmitry Osipenko пишет: >>>>> 23.04.2020 13:56, Jon Hunter пишет: >>>>>>>> So I think that part of the problem already existed prior to these >>>>>>>> patches. Without your patches I see ... >>>>>>>> >>>>>>>> [ 59.543528] tegra-i2c 7000d000.i2c: i2c transfer timed out >>>>>>>> [ 59.549036] vdd_sata,avdd_plle: failed to disable >>>>>>>> [ 59.553778] Failed to disable avdd-plle: -110 >>>>>>>> [ 59.558150] tegra-pcie 3000.pcie: failed to disable regulators: -110 >>>>>>> Does this I2C timeout happen with my patches? Could you please post full >>>>>>> logs of an older and the recent kernel versions? >>>>>> I believe that it does, but I need to check. >>>>>> >>>>> >>>>> Jon, could you please confirm that you're seeing those regulator-disable >>>>> errors with my patch? I don't see those errors in yours original log [1]. >>>>> >>>>> [1] >>>>> https://lore.kernel.org/lkml/1e259e22-c300-663a-e537-18d854e0f478@xxxxxxxxxx/ >>>>> >>>>> Again, could you please post the *full* logs? >>>>> >>>>> If regulator's disabling was "failing" before without my patch because >>>>> of the I2C interrupt being force-disabled during of NOIRQ phase, and now >>>>> regulator's disabling succeeds with my patch because IRQ is manually >>>>> handled after the timeout, then this could be bad. It means that >>>>> regulator was actually getting disabled, but I2C driver was timing out >>>>> because interrupt couldn't be handled in NOIRQ phase, which should >>>>> result in a dead PCIe on a resume from suspend since regulator's core >>>>> thinks that regulator is enabled (I2C said it failed to disable), while >>>>> it is actually disabled. >>>>> >>>>> Do you have anything plugged into the PCIe slot in yours testing farm? >>>>> It wouldn't surprise me if the plugged card isn't functional after >>>>> resume from suspend on a stable kernels. >>>>> >>>> >>>> I actually now see that interrupt is not allowed to be enabled during >>>> the NOIRQ phase: >>>> >>>> https://elixir.bootlin.com/linux/v5.7-rc3/source/kernel/irq/manage.c#L640 >>>> >>>> it should be worthwhile to turn it into a WARN_ON. >>>> >>> >>> Oh, wait! There is already a warning there.. hmm. >>> >> >> Aha, the disable depth for the I2C interrupt is 2 after >> suspend_device_irq(), that's why there is no warning. >> >> This should catch the bug and trigger the warning: >> >> --- >8 --- >> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c >> index 453a8a0f4804..fe25104d8b22 100644 >> --- a/kernel/irq/manage.c >> +++ b/kernel/irq/manage.c >> @@ -653,6 +653,8 @@ void __enable_irq(struct irq_desc *desc) >> break; >> } >> default: >> + if (desc->istate & IRQS_SUSPENDED) >> + goto err_out; >> desc->depth--; >> } >> } >> --- >8 --- >> >> Jon could you please give it a try? Will this change produce a warning >> for the I2C driver on a PCIe suspend for the v5.6 kernel? > > > Yes I can test, but I still want to know why resume is currently broken. BTW, I guess we could use the IRQF_NO_SUSPEND flag for I2C interrupt. Then it should be possible to use I2C in the late suspend without the need for atomic transfers, once RPM is resolved.
