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Message-ID: <20151204170914.GL23396@atomide.com>
Date: Fri, 4 Dec 2015 09:09:14 -0800
From: Tony Lindgren <tony@...mide.com>
To: Grygorii Strashko <grygorii.strashko@...com>
Cc: Linus Walleij <linus.walleij@...aro.org>,
Sudeep Holla <sudeep.holla@....com>,
"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
linux-omap@...r.kernel.org
Subject: Re: [PATCH 2/2] pinctrl: single: remove misuse of IRQF_NO_SUSPEND
flag
* Grygorii Strashko <grygorii.strashko@...com> [151204 08:00]:
> On 12/04/2015 05:35 PM, Tony Lindgren wrote:
> > * Grygorii Strashko <grygorii.strashko@...com> [151204 02:45]:
> >> On 12/03/2015 11:37 PM, Tony Lindgren wrote:
> >>> * Grygorii Strashko <grygorii.strashko@...com> [151203 10:36]:
> >>>>
> >>>> I think, this patch should not break our wake-up functionality.
> >>>> It will just change the moment when pcs_irq_handler() will be called:
> >>>>
> >>>> before this change:
> >>>> - suspend_enter()
> >>>> ....
> >>>> - arch_suspend_enable_irqs();
> >>>> - ^ right here
> >>>>
> >>>> after this change:
> >>>> - suspend_enter()
> >>>> ....
> >>>> dpm_resume_noirq()
> >>>> - resume_device_irqs()
> >>>> ^ here
> >>>>
> >>>> Correct? And as for me this is more safe.
> >>>
> >>> I think there's more to it though. With both applied, it produces this on
> >>> coming back up from suspend:
> >>>
> >>> PM: noirq resume of devices complete after 18.127 msecs
> >>> ------------[ cut here ]------------
> >>> WARNING: CPU: 0 PID: 123 at kernel/irq/manage.c:605 irq_set_irq_wake+0xbc/0xfc()
> >>> Unbalanced IRQ 375 wake disable
> >>> Modules linked in: ledtrig_default_on leds_gpio led_class rtc_twl twl4030_wdt
> >>> CPU: 0 PID: 123 Comm: bash Tainted: G W 4.4.0-rc3-dirty #2682
> >>> Hardware name: Generic OMAP36xx (Flattened Device Tree)
> >>> [<c0017df0>] (unwind_backtrace) from [<c0014084>] (show_stack+0x10/0x14)
> >>> <c0014084>] (show_stack) from [<c03492d0>] (dump_stack+0x84/0x9c)
> >>> [<c03492d0>] (dump_stack) from [<c003ca2c>] (warn_slowpath_common+0x7c/0xb8)
> >>> [<c003ca2c>] (warn_slowpath_common) from [<c003ca98>] (warn_slowpath_fmt+0x30/0x40)
> >>> [<c003ca98>] (warn_slowpath_fmt) from [<c009b66c>] (irq_set_irq_wake+0xbc/0xfc)
> >>> [<c009b66c>] (irq_set_irq_wake) from [<c03f0f1c>] (device_wakeup_disarm_wake_irqs+0x70/0x12c)
> >>> [<c03f0f1c>] (device_wakeup_disarm_wake_irqs) from [<c03ee4ac>] (dpm_resume_noirq+0x20c/0x2e4)
> >>> [<c03ee4ac>] (dpm_resume_noirq) from [<c0095e94>] (suspend_devices_and_enter+0x1e4/0x6bc)
> >>> [<c0095e94>] (suspend_devices_and_enter) from [<c00966c4>] (pm_suspend+0x358/0x4b8)
> >>> [<c00966c4>] (pm_suspend) from [<c0094fdc>] (state_store+0x64/0xb8)
> >>> [<c0094fdc>] (state_store) from [<c034b46c>] (kobj_attr_store+0x14/0x20)
> >>> [<c034b46c>] (kobj_attr_store) from [<c01ea4d8>] (sysfs_kf_write+0x4c/0x50)
> >>> [<c01ea4d8>] (sysfs_kf_write) from [<c01e9afc>] (kernfs_fop_write+0xbc/0x1cc)
> >>> [<c01e9afc>] (kernfs_fop_write) from [<c0171c7c>] (__vfs_write+0x24/0xd8)
> >>> [<c0171c7c>] (__vfs_write) from [<c0172520>] (vfs_write+0x94/0x154)
> >>> [<c0172520>] (vfs_write) from [<c0172d1c>] (SyS_write+0x40/0x94)
> >>> [<c0172d1c>] (SyS_write) from [<c000f760>] (ret_fast_syscall+0x0/0x1c)
> >>> ---[ end trace 321b51565e161bee ]---
> >>>
> >>> And these both need to be applied together when we have a fix for the above
> >>> as otherwise we'll get the lock recursion Sudeep mentioned in patch 2/2.
> >>>
> >>
> >> Most probably below diff will fix above issue:
> >>
> >> diff --git a/arch/arm/mach-omap2/prm_common.c
> >> b/arch/arm/mach-omap2/prm_common.c
> >> index 3fc2cbe..69cde67 100644
> >> --- a/arch/arm/mach-omap2/prm_common.c
> >> +++ b/arch/arm/mach-omap2/prm_common.c
> >> @@ -338,6 +338,7 @@ int omap_prcm_register_chain_handler(struct
> >> omap_prcm_irq_setup *irq_setup)
> >> ct->chip.irq_ack = irq_gc_ack_set_bit;
> >> ct->chip.irq_mask = irq_gc_mask_clr_bit;
> >> ct->chip.irq_unmask = irq_gc_mask_set_bit;
> >> + ct->chip.flags = IRQCHIP_SKIP_SET_WAKE;
> >>
> >> ct->regs.ack = irq_setup->ack + i * 4;
> >> ct->regs.mask = irq_setup->mask + i * 4;
> >>
> >>
> >
> > That fixes the warning on resume, but adds a new one during init:
> >
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 1 at kernel/irq/pm.c:51 irq_pm_install_action+0x9c/0xec()
> > Modules linked in:
> > CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.0-rc3-00001-g6a5e5ec #2694
> > Hardware name: Generic OMAP36xx (Flattened Device Tree)
> > [<c0017df0>] (unwind_backtrace) from [<c0014084>] (show_stack+0x10/0x14)
> > [<c0014084>] (show_stack) from [<c03492f0>] (dump_stack+0x84/0x9c)
> > [<c03492f0>] (dump_stack) from [<c003ca34>] (warn_slowpath_common+0x7c/0xb8)
> > [<c003ca34>] (warn_slowpath_common) from [<c003cb0c>] (warn_slowpath_null+0x1c/0x24)
> > [<c003cb0c>] (warn_slowpath_null) from [<c00a27d8>] (irq_pm_install_action+0x9c/0xec)
> > [<c00a27d8>] (irq_pm_install_action) from [<c009ccb0>] (__setup_irq+0x434/0x5e0)
> > [<c009ccb0>] (__setup_irq) from [<c009cfb0>] (request_threaded_irq+0xc4/0x15c)
> > [<c009cfb0>] (request_threaded_irq) from [<c08c25e8>] (omap3_pm_init+0x10c/0x400)
> > [<c08c25e8>] (omap3_pm_init) from [<c08bc66c>] (omap3_init_late+0xc/0x14)
> > [<c08bc66c>] (omap3_init_late) from [<c08b5820>] (init_machine_late+0x1c/0x90)
> > [<c08b5820>] (init_machine_late) from [<c0009804>] (do_one_initcall+0x80/0x1e0)
> > [<c0009804>] (do_one_initcall) from [<c08b2ec4>] (kernel_init_freeable+0x218/0x2e8)
> > [<c08b2ec4>] (kernel_init_freeable) from [<c064584c>] (kernel_init+0x8/0xec)
> > [<c064584c>] (kernel_init) from [<c000f7f0>] (ret_from_fork+0x14/0x24)
> > ---[ end trace 81093452bf564522 ]---
> >
>
> Sorry, I can't test it right now :(
> Potential fix below:
> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/pm34xx.c
> index 2dbd378..4e56fd9 100644
> --- a/arch/arm/mach-omap2/pm34xx.c
> +++ b/arch/arm/mach-omap2/pm34xx.c
> @@ -481,7 +481,7 @@ int __init omap3_pm_init(void)
>
> /* IO interrupt is shared with mux code */
> ret = request_irq(omap_prcm_event_to_irq("io"),
> - _prcm_int_handle_io, IRQF_SHARED | IRQF_NO_SUSPEND, "pm_io",
> + _prcm_int_handle_io, IRQF_SHARED, "pm_io",
> omap3_pm_init);
> enable_irq(omap_prcm_event_to_irq("io"));
>
> @@ -489,6 +489,7 @@ int __init omap3_pm_init(void)
> pr_err("pm: Failed to request pm_io irq\n");
> goto err2;
> }
> + enable_irq_wake(omap_prcm_event_to_irq("io"));
>
> ret = pwrdm_for_each(pwrdms_setup, NULL);
> if (ret) {
OK probably best that you take a look at it when you have a chance as
you've already spent some time on it.
Regards,
Tony
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