[PATCHv2 8/8] arm: omap3: prevent per_clkdm from attempting manual domain transitions

Tero Kristo t-kristo at ti.com
Fri Feb 24 05:11:07 EST 2012 

On Wed, 2012-02-22 at 14:37 -0800, Kevin Hilman wrote:
> Tero Kristo <t-kristo at ti.com> writes:
> 
> > On Thu, 2012-02-16 at 09:31 -0800, Kevin Hilman wrote:
> >> Tero Kristo <t-kristo at ti.com> writes:
> >> 
> >> > On Thu, 2012-02-16 at 21:15 +0530, Shilimkar, Santosh wrote:
> >> >> On Thu, Feb 16, 2012 at 8:53 PM, Tero Kristo <t-kristo at ti.com> wrote:
> >> >> > On Thu, 2012-02-16 at 15:15 +0200, Tero Kristo wrote:
> >> >> >> On Thu, 2012-02-16 at 15:27 +0530, Shilimkar, Santosh wrote:
> >> >> >> > On Thu, Feb 16, 2012 at 2:27 PM, Tero Kristo <t-kristo at ti.com> wrote:
> >> >> >> > > On Wed, 2012-02-15 at 11:37 -0800, Kevin Hilman wrote:
> >> >> >> > >> Tero Kristo <t-kristo at ti.com> writes:
> >> >> >> > >>
> >> >> >> > >> > Attempting this will cause problems especially with off-mode enabled.
> >> >> >> > >>
> >> >> >> > >> Please be more verbose about the problems seen, and the root cause(s).
> >> >> >> > >>
> >> >> >> > >
> >> >> >> > > I was actually looking forward for some help with this commit message,
> >> >> >> > > as I am still not quite sure what is going on in here. :) Here is the
> >> >> >> > > log for suspend (btw, cam_pwrdm does not go to off in mainline yet, but
> >> >> >> > > I think that is probably fixed by the patch from Paul,
> >> >> >> > > omap_set_pwrdm_state() does not work properly.) The warning comes out
> >> >> >> > > after wakeup from off-mode, and it is triggered by the disabling of
> >> >> >> > > autodeps before off-mode entry.
> >> >> >> > >
> >> >> >> > This mostly indicates that one of the per clock-domain module
> >> >> >> > clock turning ON seems to be not working well with auto deps
> >> >> >> > disabled. This leads to interconnect violation.
> >> >> >> >
> >> >> >> > if not tried already, can you put the per_clockdomain in SW_WKUP
> >> >> >> > in the low power code early resume path and see if this
> >> >> >> > error goes away.
> >> >> >>
> >> >> >> This seems to get rid of the dump also. It looks like some driver resume
> >> >> >> is not behaving nicely, I am trying to pinpoint the culprit currently
> >> >> >> and see whether it can provide more info.
> >> >> >
> >> >> > Okay, I have some more info about this now.
> >> >> >
> >> >> > What happens is that when entering off-mode, PER domain remains OFF even
> >> >> > during the execution of the exit phase from omap_sram_idle. Adding a
> >> >> > manual SW_WKUP it comes up and there are no issues. If autodeps are
> >> >> > enabled on the domain, it comes back from off mode as active.
> >> >> >
> >> >> > Looking further in the code, we have this at the end of omap_sram_idle:
> >> >> >
> >> >> >        if (per_next_state < PWRDM_POWER_ON) {
> >> >> >                per_prev_state = pwrdm_read_prev_pwrst(per_pwrdm);
> >> >> >                omap2_gpio_resume_after_idle();
> >> >> >                wake_per();
> >> >> >                if (per_prev_state == PWRDM_POWER_OFF)
> >> >> >                        omap3_per_restore_context();
> >> >> >        }
> >> >> >
> >> >> > ... which seems to assume that per domain is on. Gpio code does not
> >> >> > control any clocks currently, as it only requires the interface clock to
> >> >> > be on, and as this is autoidled....
> >> >> >
> >> >> > Any comments how we should handle this? Shall we just keep these two
> >> >> > patches for handling this or add some different hackery for the gpio
> >> >> > issue?
> >> >> >
> >> >> Good. I thought too that issue will disappear.
> >> >> The issue is pretty clear. Technically every driver pm_runtime() code should
> >> >> be able to manage a clock->clockdomain->power domain power up/down
> >> >> sequence. That should work without auto deps.
> >> >> 
> >> >> Do you narrowed down which driver resume is creating the dump ?
> >> >> UART , GPIO ?
> >> >
> >> > It is the gpio base stuff called from omap_sram_idle(), basically the
> >> > restore context part. If I force enable per domain before the code
> >> > snippet before, there is no dump, but if it is done after, I get the
> >> > dump.
> >> >
> >> > The thing is that gpio driver doesn't currently have this kind of
> >> > mechanism for the restore context part, at least not on omap3 due to
> >> > above clocking issue (only autoidled interface clock is used.)
> >> 
> >> I'm not sure if it fully addresses this, but Tarun's series converts
> >> GPIO to runtime PM.
> >> 
> >> Can you try with Tarun's series.  See the for_3.4/gpio_cleanup_fixes_v9
> >> branch here:
> >> git://gitorious.org/~tarunkanti/omap-sw-develoment/tarunkantis-linux-omap-dev.git
> >
> > It does something for the issue, but I still get this during suspend to
> > off:
> >
> > [   11.284973] PM: Syncing filesystems ... done.
> > [   11.379241] Freezing user space processes ... (elapsed 0.02 seconds)
> > done.
> > [   11.408233] Freezing remaining freezable tasks ... (elapsed 0.02
> > seconds) don
> > e.
> > [   11.439239] Suspending console(s) (use no_console_suspend to debug)
> > [   11.564178] PM: suspend of devices complete after 115.506 msecs
> > [   11.567382] PM: late suspend of devices complete after 3.204 msecs
> > [   11.567443] Disabling non-boot CPUs ...
> > [   12.004089] Powerdomain (cam_pwrdm) didn't enter target state 0
> > [   12.004119] Could not enter target state in pm_suspend
> > [   12.009368] PM: early resume of devices complete after 4.944 msecs
> > [   12.436645] PM: resume of devices complete after 426.086 msecs
> > [   12.480285] Restarting tasks ... done.
> > /sys/kernel/debu[   12.488433] ------------[ cut here ]------------
> > [   12.494415] WARNING: at arch/arm/mach-omap2/omap_hwmod.c:1604 _idle
> > +0x164/0x1
> > 7c()
> > [   12.502258] omap_hwmod: gpio6: idle state can only be entered from
> > enabled st
> > ate
> > [   12.509979] Modules linked in:
> > [   12.513214] [<c001bcd0>] (unwind_backtrace+0x0/0xf4) from
> > [<c0042968>] (warn_
> > slowpath_common+0x4c/0x64)
> > [   12.523071] [<c0042968>] (warn_slowpath_common+0x4c/0x64) from
> > [<c0042a14>] (
> > warn_slowpath_fmt+0x30/0x40)
> > [   12.533081] [<c0042a14>] (warn_slowpath_fmt+0x30/0x40) from
> > [<c0028d68>] (_id
> > le+0x164/0x17c)
> > [   12.541931] [<c0028d68>] (_idle+0x164/0x17c) from [<c00298b0>]
> > (omap_hwmod_id
> > le+0x28/0x3c)
> > [   12.550567] [<c00298b0>] (omap_hwmod_idle+0x28/0x3c) from
> > [<c003c664>] (omap_
> > device_idle_hwmods+0x24/0x3c)
> > [   12.560699] [<c003c664>] (omap_device_idle_hwmods+0x24/0x3c) from
> > [<c003c898>
> > ] (_omap_device_deactivate+0xa4/0x138)
> > [   12.571594] [<c003c898>] (_omap_device_deactivate+0xa4/0x138) from
> > [<c003c954
> >>] (omap_device_idle+0x28/0x54)
> > [   12.581909] [<c003c954>] (omap_device_idle+0x28/0x54) from
> > [<c003c99c>] (_od_
> > runtime_suspend+0x1c/0x24)
> > [   12.591735] [<c003c99c>] (_od_runtime_suspend+0x1c/0x24) from
> > [<c02c5010>] (_
> > _rpm_callback+0x2c/0x78)
> > [   12.601379] [<c02c5010>] (__rpm_callback+0x2c/0x78) from [<c02c54d0>]
> > (rpm_su
> > spend+0x264/0x6c4)
> > [   12.610504] [<c02c54d0>] (rpm_suspend+0x264/0x6c4) from [<c02c6998>]
> > (__pm_ru
> > ntime_suspend+0x5c/0x74)
> > [   12.620178] [<c02c6998>] (__pm_runtime_suspend+0x5c/0x74) from
> > [<c02731a4>] (
> > omap2_gpio_prepare_for_idle+0x50/0x64)
> > [   12.631103] [<c02731a4>] (omap2_gpio_prepare_for_idle+0x50/0x64) from
> > [<c002b
> > d30>] (omap_sram_idle+0xa0/0x3b0)
> > [   12.641571] [<c002bd30>] (omap_sram_idle+0xa0/0x3b0) from
> > [<c002c1d8>] (omap3
> > _pm_idle+0x60/0x178)
> > [   12.650848] [<c002c1d8>] (omap3_pm_idle+0x60/0x178) from [<c0015c10>]
> > (cpu_id
> > le+0xc4/0x108)
> > [   12.659606] [<c0015c10>] (cpu_idle+0xc4/0x108) from [<c0626828>]
> > (start_kerne
> > l+0x2b0/0x304)
> > [   12.668365] ---[ end trace 441b8fea2b56dcb1 ]---
> >
> >
> > Also, this goes away if I manually force wakeup for the per domain, so
> > this might be caused by some additional latency.
> >
> 
> What platform are you testing on?
> 
> When I test Tarun's series with off-mode on 3430/n900 suspend/resume
> works fine.  But when I add your v2 series, it never comes out of
> suspend, and I don't get a kernel dump either.
> 
> Can you debug this a little further so we can explain what's going on
> here?

Attached one trial patch you could try to use to see if it fixes the
issues you are seeing with 3430/n900. I'll look at Tarun's set and see
if I can figure out what is causing the warning above.

-Tero
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