Re: [PATCH] arm64: dts: renesas: r8a7796: Add CMT device nodes

[Vincent Guittot <vincent.guittot@linaro.org>]

On Fri, 25 Jan 2019 at 16:12, Biju Das <biju.das@bp.renesas.com> wrote:
>
> Hi Vincent and Rafael,
>
> Are you going to send the patch for the dead lock fix? Or Do you want me to send the patch?

I will send it once agreed with Rafael that's the best solution.
Furthermore, linux next has few more patches that modify this part so
we have to decide how to apply it for v5.0-rcX

Thanks
Vincent
>
> Please let me know.
>
> Regards,
> Biju
>
> > Subject: Re: [PATCH] arm64: dts: renesas: r8a7796: Add CMT device nodes
> >
> > Adding Rafael
> >
> > On Fri, 25 Jan 2019 at 15:48, Vincent Guittot <vincent.guittot@linaro.org>
> > wrote:
> > >
> > > On Fri, 25 Jan 2019 at 15:45, Biju Das <biju.das@bp.renesas.com> wrote:
> > > >
> > > > Hi Vincent,
> > > >
> > > > The below patch fixed deadlock.
> > > >
> > > > --- a/include/linux/pm_runtime.h
> > > > +++ b/include/linux/pm_runtime.h
> > > > @@ -105,7 +105,7 @@ static inline bool
> > > > pm_runtime_callbacks_present(struct device *dev)
> > > >
> > > >  static inline void pm_runtime_mark_last_busy(struct device *dev)  {
> > > > -       WRITE_ONCE(dev->power.last_busy, ktime_to_ns(ktime_get()));
> > > > +       WRITE_ONCE(dev->power.last_busy, ktime_get_mono_fast_ns());
> > >
> > > Ah yes. I have searched in runtime.c but  forgot to looked in
> > > pm_runtime.h
> >
> > Rafael,
> >
> > When pm-runtime is used for a clocksource, we get a deadlock because we
> > call pm_runtime_mark_last_busy() when ebaling the clocksource whereas
> > we are in the write_seqcount sequence.
> > Using ktime_get_mono_fast_ns fixes the problem because it doesn't use
> > tk_core.seq
> >
> > Regards,
> > Vincent
> >
> > >
> > > >  }
> > > >
> > > > Regards,
> > > > Biju
> > > > > -----Original Message-----
> > > > > From: Biju Das
> > > > > Sent: 25 January 2019 14:26
> > > > > To: 'Vincent Guittot' <vincent.guittot@linaro.org>
> > > > > Cc: Geert Uytterhoeven <geert@linux-m68k.org>; Sergei Shtylyov
> > > > > <sergei.shtylyov@cogentembedded.com>; Rob Herring
> > > > > <robh+dt@kernel.org>; Mark Rutland <mark.rutland@arm.com>;
> > Simon
> > > > > Horman <horms@verge.net.au>; Magnus Damm
> > <magnus.damm@gmail.com>;
> > > > > Linux-Renesas <linux-renesas- soc@vger.kernel.org>; open list:OPEN
> > > > > FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
> > > > > <devicetree@vger.kernel.org>; Geert Uytterhoeven
> > > > > <geert+renesas@glider.be>; Chris Paterson
> > > > > <Chris.Paterson2@renesas.com>; Daniel Lezcano
> > > > > <daniel.lezcano@linaro.org>; Thomas Gleixner <tglx@linutronix.de>;
> > > > > John Stultz <john.stultz@linaro.org>; Fabrizio Castro
> > > > > <fabrizio.castro@bp.renesas.com>; Samuel Holland
> > > > > <samuel@sholland.org>
> > > > > Subject: RE: [PATCH] arm64: dts: renesas: r8a7796: Add CMT device
> > > > > nodes
> > > > >
> > > > > Hi Vincent,
> > > > >
> > > > > Thanks for the update. I am still seeing the same deadlock.
> > > > >
> > > > > diff --git a/drivers/base/power/runtime.c
> > > > > b/drivers/base/power/runtime.c index fb5e2b6..a96641a 100644
> > > > > --- a/drivers/base/power/runtime.c
> > > > > +++ b/drivers/base/power/runtime.c
> > > > > @@ -155,7 +155,7 @@ u64
> > pm_runtime_autosuspend_expiration(struct
> > > > > device *dev)
> > > > >
> > > > >         expires  = READ_ONCE(dev->power.last_busy);
> > > > >         expires += (u64)autosuspend_delay * NSEC_PER_MSEC;
> > > > > -       if (expires > ktime_to_ns(ktime_get()))
> > > > > +       if (expires > ktime_get_mono_fast_ns())
> > > > >                 return expires; /* Expires in the future */
> > > > >
> > > > >         return 0;
> > > > > @@ -921,7 +921,7 @@ static enum hrtimer_restart
> > > > > pm_suspend_timer_fn(struct hrtimer *timer)
> > > > >          * If 'expires' is after the current time, we've been called
> > > > >          * too early.
> > > > >          */
> > > > > -       if (expires > 0 && expires < ktime_to_ns(ktime_get())) {
> > > > > +       if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
> > > > >                 dev->power.timer_expires = 0;
> > > > >                 rpm_suspend(dev, dev->power.timer_autosuspends ?
> > > > >                     (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC); @@ -940,7
> > > > > +940,7 @@ static enum hrtimer_restart  pm_suspend_timer_fn(struct
> > > > > hrtimer
> > > > > *timer)  int pm_schedule_suspend(struct device *dev, unsigned int
> > delay)  {
> > > > >         unsigned long flags;
> > > > > -       ktime_t expires;
> > > > > +       u64 expires;
> > > > >         int retval;
> > > > >
> > > > >         spin_lock_irqsave(&dev->power.lock, flags); @@ -957,8
> > > > > +957,8 @@ int pm_schedule_suspend(struct device *dev, unsigned int
> > delay)
> > > > >         /* Other scheduled or pending requests need to be canceled. */
> > > > >         pm_runtime_cancel_pending(dev);
> > > > >
> > > > > -       expires = ktime_add(ktime_get(), ms_to_ktime(delay));
> > > > > -       dev->power.timer_expires = ktime_to_ns(expires);
> > > > > +       expires = ktime_get_mono_fast_ns() + ((u64)delay *
> > > > > NSEC_PER_MSEC);
> > > > > +       dev->power.timer_expires = expires;
> > > > >         dev->power.timer_autosuspends = 0;
> > > > >         hrtimer_start(&dev->power.suspend_timer, expires,
> > > > > HRTIMER_MODE_ABS);
> > > > >
> > > > >
> > > > > please find the logs.
> > > > >
> > > > > root@salvator-x:~# echo  e60f0000.timer >
> > > > > /sys/devices/system/clocksource/clocksource0/current_clocksource
> > > > > [   42.769260]
> > > > > [   42.770760] ============================================
> > > > > [   42.776068] WARNING: possible recursive locking detected
> > > > > [   42.781378] 5.0.0-rc3-next-20190125-00001-gfa6709c-dirty #33 Not
> > tainted
> > > > > [   42.788076] --------------------------------------------
> > > > > [   42.793385] migration/0/11 is trying to acquire lock:
> > > > > [   42.798435] 00000000b43b7183 (tk_core.seq){----}, at:
> > > > > rpm_resume+0x5f0/0x7a8
> > > > > [   42.805497]
> > > > > [   42.805497] but task is already holding lock:
> > > > > [   42.811326] 00000000b43b7183 (tk_core.seq){----}, at:
> > > > > multi_cpu_stop+0x8c/0x140
> > > > > [   42.818641]
> > > > > [   42.818641] other info that might help us debug this:
> > > > > [   42.825165]  Possible unsafe locking scenario:
> > > > > [   42.825165]
> > > > > [   42.831080]        CPU0
> > > > > [   42.833521]        ----
> > > > > [   42.835962]   lock(tk_core.seq);
> > > > > [   42.839185]   lock(tk_core.seq);
> > > > > [   42.842409]
> > > > > [   42.842409]  *** DEADLOCK ***
> > > > > [   42.842409]
> > > > > [   42.848328]  May be due to missing lock nesting notation
> > > > > [   42.848328]
> > > > > [   42.855115] 4 locks held by migration/0/11:
> > > > > [   42.859293]  #0: 00000000a7511731 (timekeeper_lock){-.-.}, at:
> > > > > change_clocksource+0x2c/0x118
> > > > > [   42.867738]  #1: 00000000b43b7183 (tk_core.seq){----}, at:
> > > > > multi_cpu_stop+0x8c/0x140
> > > > > [   42.875484]  #2: 00000000b54c38a2 (&ch->lock){....}, at:
> > > > > sh_cmt_start+0x28/0x200
> > > > > [   42.882887]  #3: 0000000010d14eec (&(&dev->power.lock)->rlock){-
> > ...}, at:
> > > > > __rpm_callback+0xbc/0x1e8
> > > > > [   42.891937]
> > > > > [   42.891937] stack backtrace:
> > > > > [   42.896294] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.0.0-rc3-
> > next-
> > > > > 20190125-00001-gfa6709c-dirty #33
> > > > > [   42.905860] Hardware name: Renesas Salvator-X 2nd version board
> > based
> > > > > on r8a7796 (DT)
> > > > > [   42.913689] Call trace:
> > > > > [   42.916137]  dump_backtrace+0x0/0x178
> > > > > [   42.919796]  show_stack+0x14/0x20
> > > > > [   42.923111]  dump_stack+0xb0/0xec
> > > > > [   42.926425]  __lock_acquire+0xfb4/0x1c08
> > > > > [   42.930345]  lock_acquire+0xd0/0x268
> > > > > [   42.933917]  ktime_get+0x5c/0x108
> > > > > [   42.937229]  rpm_resume+0x5f0/0x7a8
> > > > > [   42.940714]  __pm_runtime_resume+0x50/0x98
> > > > > [   42.944807]  sh_cmt_start+0x84/0x200
> > > > > [   42.948380]  sh_cmt_clocksource_enable+0x28/0x48
> > > > > [   42.952995]  change_clocksource+0x84/0x118
> > > > > [   42.957087]  multi_cpu_stop+0x8c/0x140
> > > > > [   42.960834]  cpu_stopper_thread+0xac/0x120
> > > > > [   42.964931]  smpboot_thread_fn+0x1ac/0x2c8
> > > > > [   42.969024]  kthread+0x12c/0x130
> > > > > [   42.972249]  ret_from_fork+0x10/0x18
> > > > >
> > > > > Regards,
> > > > > Biju
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: Vincent Guittot <vincent.guittot@linaro.org>
> > > > > > Sent: 25 January 2019 14:06
> > > > > > Subject: Re: [PATCH] arm64: dts: renesas: r8a7796: Add CMT
> > > > > > device nodes
> > > > > >
> > > > > > Hi Biju,
> > > > > >
> > > > > > It seems that the call of mark_last_busy in rpm_resume raises
> > > > > > this
> > > > > problem.
> > > > > > We have the sequence:
> > > > > > change_clocksource
> > > > > >
> > > > > >     write_seqcount_begin
> > > > > >     ...
> > > > > >     timekeeping_update
> > > > > >         ...
> > > > > >         sh_cmt_clocksource_enable
> > > > > >             ...
> > > > > >             rpm_resume
> > > > > >                 pm_runtime_mark_last_busy
> > > > > >                     ktime_get
> > > > > >                         do
> > > > > >                             read_seqcount_begin
> > > > > >                         while read_seqcount_retry
> > > > > >     ....
> > > > > >     write_seqcount_end
> > > > > >
> > > > > > In fact, we should be safe because we haven't yet changed the
> > > > > > clocksource as we are enabling the clocksource that will be used
> > > > > > for the
> > > > > switch.
> > > > > >
> > > > > > Can you try the patch below ?
> > > > > > It uses ktime_get_mono_fast_ns instead which is lock safe for
> > > > > > such case
> > > > > >
> > > > > > ---
> > > > > >  drivers/base/power/runtime.c | 10 +++++-----
> > > > > >  1 file changed, 5 insertions(+), 5 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/base/power/runtime.c
> > > > > > b/drivers/base/power/runtime.c index 457be03..708a13f 100644
> > > > > > --- a/drivers/base/power/runtime.c
> > > > > > +++ b/drivers/base/power/runtime.c
> > > > > > @@ -130,7 +130,7 @@ u64
> > pm_runtime_autosuspend_expiration(struct
> > > > > > device *dev)  {
> > > > > >  int autosuspend_delay;
> > > > > >  u64 last_busy, expires = 0;
> > > > > > -u64 now = ktime_to_ns(ktime_get());
> > > > > > +u64 now = ktime_get_mono_fast_ns();
> > > > > >
> > > > > >  if (!dev->power.use_autosuspend)  goto out; @@ -909,7 +909,7 @@
> > > > > > static enum hrtimer_restart pm_suspend_timer_fn(struct hrtimer
> > > > > > *timer)
> > > > > >   * If 'expires' is after the current time, we've been called
> > > > > >   * too early.
> > > > > >   */
> > > > > > -if (expires > 0 && expires < ktime_to_ns(ktime_get())) {
> > > > > > +if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
> > > > > >  dev->power.timer_expires = 0;
> > > > > >  rpm_suspend(dev, dev->power.timer_autosuspends ?
> > > > > >      (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC); @@ -928,7
> > > > > > +928,7 @@ static enum hrtimer_restart
> > > > > > +pm_suspend_timer_fn(struct
> > > > > > hrtimer *timer)  int pm_schedule_suspend(struct device *dev,
> > > > > > unsigned int
> > > > > > delay)  {
> > > > > >  unsigned long flags;
> > > > > > -ktime_t expires;
> > > > > > +u64 expires;
> > > > > >  int retval;
> > > > > >
> > > > > >  spin_lock_irqsave(&dev->power.lock, flags); @@ -945,8 +945,8 @@
> > > > > int
> > > > > > pm_schedule_suspend(struct device *dev, unsigned int delay)
> > > > > >  /* Other scheduled or pending requests need to be canceled. */
> > > > > > pm_runtime_cancel_pending(dev);
> > > > > >
> > > > > > -expires = ktime_add(ktime_get(), ms_to_ktime(delay));
> > > > > > -dev->power.timer_expires = ktime_to_ns(expires);
> > > > > > +expires = ktime_get_mono_fast_ns() + (u64)delay *
> > > > > > NSEC_PER_MSEC);
> > > > > > +dev->power.timer_expires = expires;
> > > > > >  dev->power.timer_autosuspends = 0;
> > > > > > hrtimer_start(&dev->power.suspend_timer, expires,
> > > > > HRTIMER_MODE_ABS);
> > > > > >
> > > > > > --
> > > > > > 2.7.4
> > > > > >
> > > > > > Le Friday 25 Jan 2019 à 12:26:54 (+0000), Biju Das a écrit :
> > > > > > > Hi All,
> > > > > > >
> > > > > > > I have enabled lock debugging  and it is showing "possible
> > > > > > > recursive locking
> > > > > > detected "with the patch
> > ("8234f6734c5d74ac794e5517437f51c57d65f865"
> > > > > > PM-runtime: Switch autosuspend over to using hrtimers)
> > > > > > >
> > > > > > > root@salvator-x:~# echo  e60f0000.timer >
> > > > > > /sys/devices/system/clocksource/clocksource0/current_clocksource
> > > > > > > [   67.995854]
> > > > > > > [   67.997354]
> > ============================================
> > > > > > > [   68.002663] WARNING: possible recursive locking detected
> > > > > > > [   68.007974] 5.0.0-rc3-next-20190125-00005-g382822b #31 Not
> > tainted
> > > > > > > [   68.014150] --------------------------------------------
> > > > > > > [   68.019459] migration/0/11 is trying to acquire lock:
> > > > > > > [   68.024509] 0000000065de5fdf (tk_core.seq){----}, at:
> > > > > > rpm_resume+0x5f0/0x7a8
> > > > > > > [   68.031570]
> > > > > > > [   68.031570] but task is already holding lock:
> > > > > > > [   68.037399] 0000000065de5fdf (tk_core.seq){----}, at:
> > > > > > multi_cpu_stop+0x8c/0x140
> > > > > > > [   68.044714]
> > > > > > > [   68.044714] other info that might help us debug this:
> > > > > > > [   68.051237]  Possible unsafe locking scenario:
> > > > > > > [   68.051237]
> > > > > > > [   68.057153]        CPU0
> > > > > > > [   68.059594]        ----
> > > > > > > [   68.062034]   lock(tk_core.seq);
> > > > > > > [   68.065258]   lock(tk_core.seq);
> > > > > > > [   68.068482]
> > > > > > > [   68.068482]  *** DEADLOCK ***
> > > > > > > [   68.068482]
> > > > > > > [   68.074402]  May be due to missing lock nesting notation
> > > > > > > [   68.074402]
> > > > > > > [   68.081188] 4 locks held by migration/0/11:
> > > > > > > [   68.085366]  #0: 00000000463b6446 (timekeeper_lock){-.-.}, at:
> > > > > > change_clocksource+0x2c/0x118
> > > > > > > [   68.093812]  #1: 0000000065de5fdf (tk_core.seq){----}, at:
> > > > > > multi_cpu_stop+0x8c/0x140
> > > > > > > [   68.101558]  #2: 0000000098b45550 (&ch->lock){....}, at:
> > > > > > sh_cmt_start+0x28/0x200
> > > > > > > [   68.108961]  #3: 00000000da0f4e80 (&(&dev->power.lock)-
> > >rlock){-...},
> > > > > at:
> > > > > > __rpm_callback+0xbc/0x1e8
> > > > > > > [   68.118011]
> > > > > > > [   68.118011] stack backtrace:
> > > > > > > [   68.122368] CPU: 0 PID: 11 Comm: migration/0 Not tainted 5.0.0-
> > rc3-
> > > > > next-
> > > > > > 20190125-00005-g382822b #31
> > > > > > > [   68.131412] Hardware name: Renesas Salvator-X 2nd version
> > board
> > > > > based
> > > > > > on r8a7796 (DT)
> > > > > > > [   68.139240] Call trace:
> > > > > > > [   68.141687]  dump_backtrace+0x0/0x178
> > > > > > > [   68.145346]  show_stack+0x14/0x20
> > > > > > > [   68.148661]  dump_stack+0xb0/0xec
> > > > > > > [   68.151975]  __lock_acquire+0xfb4/0x1c08
> > > > > > > [   68.155894]  lock_acquire+0xd0/0x268
> > > > > > > [   68.159467]  ktime_get+0x5c/0x108
> > > > > > > [   68.162779]  rpm_resume+0x5f0/0x7a8
> > > > > > > [   68.166265]  __pm_runtime_resume+0x50/0x98
> > > > > > > [   68.170358]  sh_cmt_start+0x84/0x200
> > > > > > > [   68.173931]  sh_cmt_clocksource_enable+0x28/0x48
> > > > > > > [   68.178546]  change_clocksource+0x84/0x118
> > > > > > > [   68.182639]  multi_cpu_stop+0x8c/0x140
> > > > > > > [   68.186385]  cpu_stopper_thread+0xac/0x120
> > > > > > > [   68.190481]  smpboot_thread_fn+0x1ac/0x2c8
> > > > > > > [   68.194574]  kthread+0x12c/0x130
> > > > > > > [   68.197800]  ret_from_fork+0x10/0x18
> > > > > > >
> > > > > > > Regards,
> > > > > > > Biju
> > > > > > >
> > > > > > > > -----Original Message-----
> > > > > > > > From: Biju Das
> > > > > > > > Sent: 25 January 2019 11:27
> > > > > > > > To: 'Geert Uytterhoeven' <geert@linux-m68k.org>; Vincent
> > > > > > > > Guittot <vincent.guittot@linaro.org>; Sergei Shtylyov
> > > > > > > > <sergei.shtylyov@cogentembedded.com>
> > > > > > > > Cc: Rob Herring <robh+dt@kernel.org>; Mark Rutland
> > > > > > > > <mark.rutland@arm.com>; Simon Horman
> > <horms@verge.net.au>;
> > > > > > Magnus
> > > > > > > > Damm <magnus.damm@gmail.com>; Linux-Renesas <linux-
> > renesas-
> > > > > > > > soc@vger.kernel.org>; open list:OPEN FIRMWARE AND
> > FLATTENED
> > > > > > DEVICE
> > > > > > > > TREE BINDINGS <devicetree@vger.kernel.org>; Geert
> > > > > > > > Uytterhoeven <geert+renesas@glider.be>; Chris Paterson
> > > > > > > > <Chris.Paterson2@renesas.com>; Daniel Lezcano
> > > > > > > > <daniel.lezcano@linaro.org>; Thomas Gleixner
> > > > > > > > <tglx@linutronix.de>; John Stultz <john.stultz@linaro.org>;
> > > > > > > > Fabrizio Castro <fabrizio.castro@bp.renesas.com>; Samuel
> > > > > > > > Holland <samuel@sholland.org>
> > > > > > > > Subject: RE: [PATCH] arm64: dts: renesas: r8a7796: Add CMT
> > > > > > > > device nodes
> > > > > > > >
> > > > > > > > Hi Geert,
> > > > > > > >
> > > > > > > > Thanks for the feedback. I started testing CMT on latest
> > > > > > > > kernel(Linux-next-
> > > > > > > > 20190125 and also renesas-dev) and found that it is broken
> > > > > > > > on R-Car M3-W device.
> > > > > > > >
> > > > > > > > On further investigation the patch ("
> > > > > > > > 8234f6734c5d74ac794e5517437f51c57d65f865"   PM-runtime:
> > Switch
> > > > > > > > autosuspend over to using hrtimers)  is causing the issue.
> > > > > > > >
> > > > > > > > During clock source switching, It calls the function
> > "sh_cmt_enable"
> > > > > > > > which calls " pm_runtime_get_sync(&ch->cmt->pdev->dev);"
> > > > > > > > and after that console freezes.
> > > > > > > >
> > > > > > > > Sergei: Have you noticed this issue  on R-Car V3M and V3H
> > > > > > > > boards with latest kernel?
> > > > > > > >
> > > > > > > > Regards,
> > > > > > > > Biju
> > > > > > > >
> > > > > > > > > -----Original Message-----
> > > > > > > > > From: linux-renesas-soc-owner@vger.kernel.org
> > > > > > > > > <linux-renesas-soc- owner@vger.kernel.org> On Behalf Of
> > > > > > > > > Geert Uytterhoeven
> > > > > > > > > Sent: 24 January 2019 10:16
> > > > > > > > > To: Biju Das <biju.das@bp.renesas.com>
> > > > > > > > > Cc: Rob Herring <robh+dt@kernel.org>; Mark Rutland
> > > > > > > > > <mark.rutland@arm.com>; Simon Horman
> > <horms@verge.net.au>;
> > > > > > > > Magnus Damm
> > > > > > > > > <magnus.damm@gmail.com>; Linux-Renesas <linux-renesas-
> > > > > > > > > soc@vger.kernel.org>; open list:OPEN FIRMWARE AND
> > > > > > > > > FLATTENED
> > > > > > DEVICE
> > > > > > > > > TREE BINDINGS <devicetree@vger.kernel.org>; Geert
> > > > > > > > > Uytterhoeven <geert+renesas@glider.be>; Chris Paterson
> > > > > > > > > <Chris.Paterson2@renesas.com>; Daniel Lezcano
> > > > > > > > > <daniel.lezcano@linaro.org>; Thomas Gleixner
> > > > > > > > > <tglx@linutronix.de>; John Stultz
> > > > > > > > > <john.stultz@linaro.org>; Fabrizio Castro
> > > > > > > > > <fabrizio.castro@bp.renesas.com>; Samuel Holland
> > > > > > > > <samuel@sholland.org>
> > > > > > > > > Subject: Re: [PATCH] arm64: dts: renesas: r8a7796: Add CMT
> > > > > > > > > device nodes
> > > > > > > > >
> > > > > > > > > Hi Biju,
> > > > > > > > >
> > > > > > > > > On Fri, Oct 26, 2018 at 10:32 AM Biju Das
> > > > > > > > > <biju.das@bp.renesas.com>
> > > > > > > > wrote:
> > > > > > > > > > This patch adds CMT{0|1|2|3} device nodes for r8a7796 SoC.
> > > > > > > > > >
> > > > > > > > > > Signed-off-by: Biju Das <biju.das@bp.renesas.com>
> > > > > > > > > > ---
> > > > > > > > > > This patch is tested against renesas-dev
> > > > > > > > > >
> > > > > > > > > > I have executed on inconsistency-check, nanosleep and
> > > > > > > > > > clocksource_switch selftests on this arm64 SoC. The
> > > > > > > > > > inconsistency-check and nanosleep tests are working
> > > > > > > > > > fine.The clocksource_switch asynchronous test is failing
> > > > > > > > > > due to inconsistency-check
> > > > > > > > > failure on "arch_sys_counter".
> > > > > > > > > >
> > > > > > > > > > But if i skip the clocksource_switching of
> > > > > > > > > > "arch_sys_counter", the asynchronous test is passing for
> > CMT0/1/2/3 timer.
> > > > > > > > > >
> > > > > > > > > > Has any one noticed this issue?
> > > > > > > > >
> > > > > > > > > clockevents/next now has commit 7cd6dca3600d8d71
> > > > > > > > > ("clocksource/drivers/arch_timer: Workaround for Allwinner
> > > > > > > > > A64 timer instability").  Perhaps this is related, and the
> > > > > > > > > same test program may indicate similar issues?
> > > > > > > > >
> > > > > > > > > See also
> > > > > > > > > https://lore.kernel.org/lkml/20190113021719.46457-2-
> > > > > > > > > samuel@sholland.org/
> > > > > > > > >
> > > > > > > > > Gr{oetje,eeting}s,
> > > > > > > > >
> > > > > > > > >                         Geert
> > > > > > > > >
> > > > > > > > > --
> > > > > > > > > Geert Uytterhoeven -- There's lots of Linux beyond ia32 --
> > > > > > > > > geert@linux- m68k.org
> > > > > > > > >
> > > > > > > > > In personal conversations with technical people, I call
> > > > > > > > > myself a hacker. But when I'm talking to journalists I
> > > > > > > > > just say "programmer" or
> > > > > > > > something like that.
> > > > > > > > >                                 -- Linus Torvalds
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Renesas Electronics Europe Ltd, Dukes Meadow, Millboard Road,
> > > > > > > Bourne
> > > > > > End, Buckinghamshire, SL8 5FH, UK. Registered in England & Wales
> > > > > > under Registered No. 04586709.
> > > >
> > > >
> > > >
> > > > Renesas Electronics Europe Ltd, Dukes Meadow, Millboard Road, Bourne
> > End, Buckinghamshire, SL8 5FH, UK. Registered in England & Wales under
> > Registered No. 04586709.
>
>
>
> Renesas Electronics Europe Ltd, Dukes Meadow, Millboard Road, Bourne End, Buckinghamshire, SL8 5FH, UK. Registered in England & Wales under Registered No. 04586709.