Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Jon Hunter]

Hi Rafael,

On 13/06/2019 22:59, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> attempted to avoid a problem with devices whose drivers want them to
> stay in D0 over suspend-to-idle and resume, but it did not go as far
> as it should with that.
> 
> Namely, first of all, the power state of a PCI bridge with a
> downstream device in D0 must be D0 (based on the PCI PM spec r1.2,
> sec 6, table 6-1, if the bridge is not in D0, there can be no PCI
> transactions on its secondary bus), but that is not actively enforced
> during system-wide PM transitions, so use the skip_bus_pm flag
> introduced by commit d491f2b75237 for that.
> 
> Second, the configuration of devices left in D0 (whatever the reason)
> during suspend-to-idle need not be changed and attempting to put them
> into D0 again by force is pointless, so explicitly avoid doing that.
> 
> Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

I have noticed a regression in both the mainline and -next branches on
one of our boards when testing suspend. The bisect is point to this
commit and reverting on top of mainline does fix the problem. So far I
have not looked at this in close detail but kernel log is showing ...

[   52.775138] PM: suspend entry (deep)
[   52.779040] Filesystems sync: 0.000 seconds
[   52.783476] Freezing user space processes ... (elapsed 0.001 seconds) done.
[   52.791891] OOM killer disabled.
[   52.795174] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[   52.803752] printk: Suspending console(s) (use no_console_suspend to debug)
[   52.823750] r8169 0000:01:00.0 eth0: Link is Down
[   52.823908] pci_generic_config_write32: 22 callbacks suppressed
[   52.823914] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x9c may corrupt adjacent RW1C bits
[   53.045383] Disabling non-boot CPUs ...
[   53.048481] Entering suspend state LP1
[   53.048508] Enabling non-boot CPUs ...
[   53.049402] CPU1 is up
[   53.050182] CPU2 is up
[   53.051017] CPU3 is up
[   53.051613] tegra-pcie 1003000.pcie: probing port 1, using 1 lanes
[   53.069689] pcieport 0000:00:02.0: nv_msi_ht_cap_quirk didn't locate host bridge
[   53.093751] r8169 0000:01:00.0: Refused to change power state, currently in D3
[   53.156586] tegra-pcie 1003000.pcie: Slot present pin change, signature: 00000004
[   53.156593] tegra-pcie 1003000.pcie: Response decoding error, signature: 10010045
[   53.156596] tegra-pcie 1003000.pcie:   FPCI address: fe10010044
[   53.156711] tegra-pcie 1003000.pcie: Response decoding error, signature: 2000000c
[   53.156714] tegra-pcie 1003000.pcie:   FPCI address:   2000000c
[   53.156719] tegra-pcie 1003000.pcie: Response decoding error, signature: 20000001
[   53.156722] tegra-pcie 1003000.pcie:   FPCI address:   20000000
[   53.177372] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x88 may corrupt adjacent RW1C bits
[   53.177379] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x90 may corrupt adjacent RW1C bits
[   53.177384] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x98 may corrupt adjacent RW1C bits
[   53.177389] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x9c may corrupt adjacent RW1C bits
[   53.177394] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0xa8 may corrupt adjacent RW1C bits
[   53.177399] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0xb0 may corrupt adjacent RW1C bits
[   53.177451] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x52 may corrupt adjacent RW1C bits
[   53.177461] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x52 may corrupt adjacent RW1C bits
[   53.177470] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x5c may corrupt adjacent RW1C bits
[   53.187746] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   53.188030] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.224105] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.224394] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.224679] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.224966] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.225247] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.225528] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.225813] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.226089] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.226372] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.226654] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.226934] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.227213] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.227495] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.227773] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.228050] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.228326] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.228609] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.228896] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.229181] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.064108] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.064429] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.064713] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.064996] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.065013] Generic Realtek PHY r8169-100:00: Master/Slave resolution failed, maybe conflicting manual settings?
[   54.065016] ------------[ cut here ]------------
[   54.065025] WARNING: CPU: 1 PID: 617 at /home/jonathanh/workdir/tegra/mlt-linux_torvalds/kernel/drivers/net/phy/phy.c:735 phy_error+0x1c/0x54
[   54.065028] Modules linked in: ttm
[   54.065039] CPU: 1 PID: 617 Comm: kworker/1:2 Not tainted 5.2.0-rc6 #1
[   54.065041] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
[   54.065049] Workqueue: events_power_efficient phy_state_machine
[   54.065068] [<c0112244>] (unwind_backtrace) from [<c010cad8>] (show_stack+0x10/0x14)
[   54.065075] [<c010cad8>] (show_stack) from [<c0a60624>] (dump_stack+0xb4/0xc8)
[   54.065082] [<c0a60624>] (dump_stack) from [<c0123cbc>] (__warn+0xe0/0xf8)
[   54.065090] [<c0123cbc>] (__warn) from [<c0123dec>] (warn_slowpath_null+0x40/0x48)
[   54.065095] [<c0123dec>] (warn_slowpath_null) from [<c06173f8>] (phy_error+0x1c/0x54)
[   54.065101] [<c06173f8>] (phy_error) from [<c06184ec>] (phy_state_machine+0x64/0x1c0)
[   54.065112] [<c06184ec>] (phy_state_machine) from [<c013e744>] (process_one_work+0x204/0x578)
[   54.065119] [<c013e744>] (process_one_work) from [<c013f444>] (worker_thread+0x44/0x584)
[   54.065123] [<c013f444>] (worker_thread) from [<c01445d4>] (kthread+0x148/0x150)
[   54.065128] [<c01445d4>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
[   54.065131] Exception stack(0xe91b3fb0 to 0xe91b3ff8)
[   54.065134] 3fa0:                                     00000000 00000000 00000000 00000000
[   54.065138] 3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[   54.065141] 3fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[   54.065145] ---[ end trace f59188238fc6fed4 ]---
[   54.065168] r8169 0000:01:00.0 eth0: Link is Down
[   54.075411] r8169 0000:01:00.0 eth0: rtl_chipcmd_cond == 1 (loop: 100, delay: 100).
[   54.085652] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.095833] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.106017] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.116214] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.126419] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.136613] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.146829] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.157030] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.167223] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.177433] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.187635] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.197840] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.199008] r8169 0000:01:00.0 eth0: rtl_ephyar_cond == 1 (loop: 100, delay: 10).
[   54.200173] r8169 0000:01:00.0 eth0: rtl_ephyar_cond == 1 (loop: 100, delay: 10).
[   54.201336] r8169 0000:01:00.0 eth0: rtl_ephyar_cond == 1 (loop: 100, delay: 10).
[   54.202502] r8169 0000:01:00.0 eth0: rtl_ephyar_cond == 1 (loop: 100, delay: 10).
[   54.203018] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.546178] ata1: SATA link down (SStatus 0 SControl 300)
[   56.810813] OOM killer enabled.
[   56.813953] Restarting tasks ... done.
[   56.819622] PM: suspend exit
[   72.504381] nfs: server 192.168.99.1 not responding, still trying
[   78.104369] nfs: server 192.168.99.1 not responding, still trying

Let me know if you have any thoughts.

Cheers
Jon

-- 
nvpublic

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Rafael J. Wysocki]

On Mon, Jun 24, 2019 at 2:43 PM Jon Hunter <jonathanh@nvidia.com> wrote:
>
> Hi Rafael,
>
> On 13/06/2019 22:59, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> > attempted to avoid a problem with devices whose drivers want them to
> > stay in D0 over suspend-to-idle and resume, but it did not go as far
> > as it should with that.
> >
> > Namely, first of all, the power state of a PCI bridge with a
> > downstream device in D0 must be D0 (based on the PCI PM spec r1.2,
> > sec 6, table 6-1, if the bridge is not in D0, there can be no PCI
> > transactions on its secondary bus), but that is not actively enforced
> > during system-wide PM transitions, so use the skip_bus_pm flag
> > introduced by commit d491f2b75237 for that.
> >
> > Second, the configuration of devices left in D0 (whatever the reason)
> > during suspend-to-idle need not be changed and attempting to put them
> > into D0 again by force is pointless, so explicitly avoid doing that.
> >
> > Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> > Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>
> I have noticed a regression in both the mainline and -next branches on
> one of our boards when testing suspend. The bisect is point to this
> commit and reverting on top of mainline does fix the problem. So far I
> have not looked at this in close detail but kernel log is showing ...

Can you please collect a log like that, but with dynamic debug in
pci-driver.c enabled?

Note that reverting this commit is rather out of the question, so we
need to get to the bottom of the failure.

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Rafael J. Wysocki]

On Mon, Jun 24, 2019 at 11:37 PM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> On Mon, Jun 24, 2019 at 2:43 PM Jon Hunter <jonathanh@nvidia.com> wrote:
> >
> > Hi Rafael,
> >
> > On 13/06/2019 22:59, Rafael J. Wysocki wrote:
> > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > >
> > > Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> > > attempted to avoid a problem with devices whose drivers want them to
> > > stay in D0 over suspend-to-idle and resume, but it did not go as far
> > > as it should with that.
> > >
> > > Namely, first of all, the power state of a PCI bridge with a
> > > downstream device in D0 must be D0 (based on the PCI PM spec r1.2,
> > > sec 6, table 6-1, if the bridge is not in D0, there can be no PCI
> > > transactions on its secondary bus), but that is not actively enforced
> > > during system-wide PM transitions, so use the skip_bus_pm flag
> > > introduced by commit d491f2b75237 for that.
> > >
> > > Second, the configuration of devices left in D0 (whatever the reason)
> > > during suspend-to-idle need not be changed and attempting to put them
> > > into D0 again by force is pointless, so explicitly avoid doing that.
> > >
> > > Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> > > Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> >
> > I have noticed a regression in both the mainline and -next branches on
> > one of our boards when testing suspend. The bisect is point to this
> > commit and reverting on top of mainline does fix the problem. So far I
> > have not looked at this in close detail but kernel log is showing ...
>
> Can you please collect a log like that, but with dynamic debug in
> pci-driver.c enabled?
>
> Note that reverting this commit is rather out of the question, so we
> need to get to the bottom of the failure.

I suspect that there is a problem with the pm_suspend_via_firmware()
check which returns 'false' on the affected board, but the platform
actually removes power from devices left in D0 during suspend.

I guess it would be more appropriate to check something like
pm_suspend_no_platform() which would return 'true' in the
suspend-to-idle patch w/ ACPI.

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Rafael J. Wysocki]

On Tuesday, June 25, 2019 12:20:26 AM CEST Rafael J. Wysocki wrote:
> On Mon, Jun 24, 2019 at 11:37 PM Rafael J. Wysocki <rafael@kernel.org> wrote:
> >
> > On Mon, Jun 24, 2019 at 2:43 PM Jon Hunter <jonathanh@nvidia.com> wrote:
> > >
> > > Hi Rafael,
> > >
> > > On 13/06/2019 22:59, Rafael J. Wysocki wrote:
> > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > >
> > > > Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> > > > attempted to avoid a problem with devices whose drivers want them to
> > > > stay in D0 over suspend-to-idle and resume, but it did not go as far
> > > > as it should with that.
> > > >
> > > > Namely, first of all, the power state of a PCI bridge with a
> > > > downstream device in D0 must be D0 (based on the PCI PM spec r1.2,
> > > > sec 6, table 6-1, if the bridge is not in D0, there can be no PCI
> > > > transactions on its secondary bus), but that is not actively enforced
> > > > during system-wide PM transitions, so use the skip_bus_pm flag
> > > > introduced by commit d491f2b75237 for that.
> > > >
> > > > Second, the configuration of devices left in D0 (whatever the reason)
> > > > during suspend-to-idle need not be changed and attempting to put them
> > > > into D0 again by force is pointless, so explicitly avoid doing that.
> > > >
> > > > Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> > > > Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > >
> > > I have noticed a regression in both the mainline and -next branches on
> > > one of our boards when testing suspend. The bisect is point to this
> > > commit and reverting on top of mainline does fix the problem. So far I
> > > have not looked at this in close detail but kernel log is showing ...
> >
> > Can you please collect a log like that, but with dynamic debug in
> > pci-driver.c enabled?
> >
> > Note that reverting this commit is rather out of the question, so we
> > need to get to the bottom of the failure.
> 
> I suspect that there is a problem with the pm_suspend_via_firmware()
> check which returns 'false' on the affected board, but the platform
> actually removes power from devices left in D0 during suspend.
> 
> I guess it would be more appropriate to check something like
> pm_suspend_no_platform() which would return 'true' in the
> suspend-to-idle patch w/ ACPI.

So I wonder if the patch below makes any difference?

---
 drivers/pci/pci-driver.c |    8 ++++----
 include/linux/suspend.h  |   26 ++++++++++++++++++++++++--
 kernel/power/suspend.c   |    3 +++
 3 files changed, 31 insertions(+), 6 deletions(-)

Index: linux-pm/include/linux/suspend.h
===================================================================
--- linux-pm.orig/include/linux/suspend.h
+++ linux-pm/include/linux/suspend.h
@@ -209,8 +209,9 @@ extern int suspend_valid_only_mem(suspen
 
 extern unsigned int pm_suspend_global_flags;
 
-#define PM_SUSPEND_FLAG_FW_SUSPEND	(1 << 0)
-#define PM_SUSPEND_FLAG_FW_RESUME	(1 << 1)
+#define PM_SUSPEND_FLAG_FW_SUSPEND	BIT(0)
+#define PM_SUSPEND_FLAG_FW_RESUME	BIT(1)
+#define PM_SUSPEND_FLAG_NO_PLATFORM	BIT(2)
 
 static inline void pm_suspend_clear_flags(void)
 {
@@ -227,6 +228,11 @@ static inline void pm_set_resume_via_fir
 	pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_RESUME;
 }
 
+static inline void pm_set_suspend_no_platform(void)
+{
+	pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM;
+}
+
 /**
  * pm_suspend_via_firmware - Check if platform firmware will suspend the system.
  *
@@ -268,6 +274,22 @@ static inline bool pm_resume_via_firmwar
 	return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME);
 }
 
+/**
+ * pm_suspend_no_platform - Check if platform may change device power states.
+ *
+ * To be called during system-wide power management transitions to sleep states
+ * or during the subsequent system-wide transitions back to the working state.
+ *
+ * Return 'true' if the power states of devices remain under full control of the
+ * kernel throughout the system-wide suspend and resume cycle in progress (that
+ * is, if a device is put into a certain power state during suspend, it can be
+ * expected to remain in that state during resume).
+ */
+static inline bool pm_suspend_no_platform(void)
+{
+	return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM);
+}
+
 /* Suspend-to-idle state machnine. */
 enum s2idle_states {
 	S2IDLE_STATE_NONE,      /* Not suspended/suspending. */
Index: linux-pm/kernel/power/suspend.c
===================================================================
--- linux-pm.orig/kernel/power/suspend.c
+++ linux-pm/kernel/power/suspend.c
@@ -493,6 +493,9 @@ int suspend_devices_and_enter(suspend_st
 
 	pm_suspend_target_state = state;
 
+	if (state == PM_SUSPEND_TO_IDLE)
+		pm_set_suspend_no_platform();
+
 	error = platform_suspend_begin(state);
 	if (error)
 		goto Close;
Index: linux-pm/drivers/pci/pci-driver.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-driver.c
+++ linux-pm/drivers/pci/pci-driver.c
@@ -870,7 +870,7 @@ static int pci_pm_suspend_noirq(struct d
 			pci_dev->bus->self->skip_bus_pm = true;
 	}
 
-	if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) {
+	if (pci_dev->skip_bus_pm && pm_suspend_no_platform()) {
 		dev_dbg(dev, "PCI PM: Skipped\n");
 		goto Fixup;
 	}
@@ -925,10 +925,10 @@ static int pci_pm_resume_noirq(struct de
 	/*
 	 * In the suspend-to-idle case, devices left in D0 during suspend will
 	 * stay in D0, so it is not necessary to restore or update their
-	 * configuration here and attempting to put them into D0 again may
-	 * confuse some firmware, so avoid doing that.
+	 * configuration here and attempting to put them into D0 again is
+	 * pointless, so avoid doing that.
 	 */
-	if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware())
+	if (!(pci_dev->skip_bus_pm && pm_suspend_no_platform()))
 		pci_pm_default_resume_early(pci_dev);
 
 	pci_fixup_device(pci_fixup_resume_early, pci_dev);

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Jon Hunter]

On 25/06/2019 00:09, Rafael J. Wysocki wrote:
> On Tuesday, June 25, 2019 12:20:26 AM CEST Rafael J. Wysocki wrote:
>> On Mon, Jun 24, 2019 at 11:37 PM Rafael J. Wysocki <rafael@kernel.org> wrote:
>>>
>>> On Mon, Jun 24, 2019 at 2:43 PM Jon Hunter <jonathanh@nvidia.com> wrote:
>>>>
>>>> Hi Rafael,
>>>>
>>>> On 13/06/2019 22:59, Rafael J. Wysocki wrote:
>>>>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>>>
>>>>> Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
>>>>> attempted to avoid a problem with devices whose drivers want them to
>>>>> stay in D0 over suspend-to-idle and resume, but it did not go as far
>>>>> as it should with that.
>>>>>
>>>>> Namely, first of all, the power state of a PCI bridge with a
>>>>> downstream device in D0 must be D0 (based on the PCI PM spec r1.2,
>>>>> sec 6, table 6-1, if the bridge is not in D0, there can be no PCI
>>>>> transactions on its secondary bus), but that is not actively enforced
>>>>> during system-wide PM transitions, so use the skip_bus_pm flag
>>>>> introduced by commit d491f2b75237 for that.
>>>>>
>>>>> Second, the configuration of devices left in D0 (whatever the reason)
>>>>> during suspend-to-idle need not be changed and attempting to put them
>>>>> into D0 again by force is pointless, so explicitly avoid doing that.
>>>>>
>>>>> Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
>>>>> Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>>> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>>>>> Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>>>
>>>> I have noticed a regression in both the mainline and -next branches on
>>>> one of our boards when testing suspend. The bisect is point to this
>>>> commit and reverting on top of mainline does fix the problem. So far I
>>>> have not looked at this in close detail but kernel log is showing ...
>>>
>>> Can you please collect a log like that, but with dynamic debug in
>>> pci-driver.c enabled?
>>>
>>> Note that reverting this commit is rather out of the question, so we
>>> need to get to the bottom of the failure.
>>
>> I suspect that there is a problem with the pm_suspend_via_firmware()
>> check which returns 'false' on the affected board, but the platform
>> actually removes power from devices left in D0 during suspend.
>>
>> I guess it would be more appropriate to check something like
>> pm_suspend_no_platform() which would return 'true' in the
>> suspend-to-idle patch w/ ACPI.
> 
> So I wonder if the patch below makes any difference?

Thanks. I will try this now and let you know.

Cheers!
Jon

-- 
nvpublic

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Jon Hunter]

On 25/06/2019 00:09, Rafael J. Wysocki wrote:
> On Tuesday, June 25, 2019 12:20:26 AM CEST Rafael J. Wysocki wrote:
>> On Mon, Jun 24, 2019 at 11:37 PM Rafael J. Wysocki <rafael@kernel.org> wrote:
>>>
>>> On Mon, Jun 24, 2019 at 2:43 PM Jon Hunter <jonathanh@nvidia.com> wrote:
>>>>
>>>> Hi Rafael,
>>>>
>>>> On 13/06/2019 22:59, Rafael J. Wysocki wrote:
>>>>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>>>
>>>>> Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
>>>>> attempted to avoid a problem with devices whose drivers want them to
>>>>> stay in D0 over suspend-to-idle and resume, but it did not go as far
>>>>> as it should with that.
>>>>>
>>>>> Namely, first of all, the power state of a PCI bridge with a
>>>>> downstream device in D0 must be D0 (based on the PCI PM spec r1.2,
>>>>> sec 6, table 6-1, if the bridge is not in D0, there can be no PCI
>>>>> transactions on its secondary bus), but that is not actively enforced
>>>>> during system-wide PM transitions, so use the skip_bus_pm flag
>>>>> introduced by commit d491f2b75237 for that.
>>>>>
>>>>> Second, the configuration of devices left in D0 (whatever the reason)
>>>>> during suspend-to-idle need not be changed and attempting to put them
>>>>> into D0 again by force is pointless, so explicitly avoid doing that.
>>>>>
>>>>> Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
>>>>> Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>>> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>>>>> Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>>>
>>>> I have noticed a regression in both the mainline and -next branches on
>>>> one of our boards when testing suspend. The bisect is point to this
>>>> commit and reverting on top of mainline does fix the problem. So far I
>>>> have not looked at this in close detail but kernel log is showing ...
>>>
>>> Can you please collect a log like that, but with dynamic debug in
>>> pci-driver.c enabled?
>>>
>>> Note that reverting this commit is rather out of the question, so we
>>> need to get to the bottom of the failure.
>>
>> I suspect that there is a problem with the pm_suspend_via_firmware()
>> check which returns 'false' on the affected board, but the platform
>> actually removes power from devices left in D0 during suspend.
>>
>> I guess it would be more appropriate to check something like
>> pm_suspend_no_platform() which would return 'true' in the
>> suspend-to-idle patch w/ ACPI.
> 
> So I wonder if the patch below makes any difference?
> 
> ---
>  drivers/pci/pci-driver.c |    8 ++++----
>  include/linux/suspend.h  |   26 ++++++++++++++++++++++++--
>  kernel/power/suspend.c   |    3 +++
>  3 files changed, 31 insertions(+), 6 deletions(-)
> 
> Index: linux-pm/include/linux/suspend.h
> ===================================================================
> --- linux-pm.orig/include/linux/suspend.h
> +++ linux-pm/include/linux/suspend.h
> @@ -209,8 +209,9 @@ extern int suspend_valid_only_mem(suspen
>  
>  extern unsigned int pm_suspend_global_flags;
>  
> -#define PM_SUSPEND_FLAG_FW_SUSPEND	(1 << 0)
> -#define PM_SUSPEND_FLAG_FW_RESUME	(1 << 1)
> +#define PM_SUSPEND_FLAG_FW_SUSPEND	BIT(0)
> +#define PM_SUSPEND_FLAG_FW_RESUME	BIT(1)
> +#define PM_SUSPEND_FLAG_NO_PLATFORM	BIT(2)
>  
>  static inline void pm_suspend_clear_flags(void)
>  {
> @@ -227,6 +228,11 @@ static inline void pm_set_resume_via_fir
>  	pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_RESUME;
>  }
>  
> +static inline void pm_set_suspend_no_platform(void)
> +{
> +	pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM;
> +}
> +
>  /**
>   * pm_suspend_via_firmware - Check if platform firmware will suspend the system.
>   *
> @@ -268,6 +274,22 @@ static inline bool pm_resume_via_firmwar
>  	return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME);
>  }
>  
> +/**
> + * pm_suspend_no_platform - Check if platform may change device power states.
> + *
> + * To be called during system-wide power management transitions to sleep states
> + * or during the subsequent system-wide transitions back to the working state.
> + *
> + * Return 'true' if the power states of devices remain under full control of the
> + * kernel throughout the system-wide suspend and resume cycle in progress (that
> + * is, if a device is put into a certain power state during suspend, it can be
> + * expected to remain in that state during resume).
> + */
> +static inline bool pm_suspend_no_platform(void)
> +{
> +	return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM);
> +}
> +
>  /* Suspend-to-idle state machnine. */
>  enum s2idle_states {
>  	S2IDLE_STATE_NONE,      /* Not suspended/suspending. */
> Index: linux-pm/kernel/power/suspend.c
> ===================================================================
> --- linux-pm.orig/kernel/power/suspend.c
> +++ linux-pm/kernel/power/suspend.c
> @@ -493,6 +493,9 @@ int suspend_devices_and_enter(suspend_st
>  
>  	pm_suspend_target_state = state;
>  
> +	if (state == PM_SUSPEND_TO_IDLE)
> +		pm_set_suspend_no_platform();
> +
>  	error = platform_suspend_begin(state);
>  	if (error)
>  		goto Close;
> Index: linux-pm/drivers/pci/pci-driver.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-driver.c
> +++ linux-pm/drivers/pci/pci-driver.c
> @@ -870,7 +870,7 @@ static int pci_pm_suspend_noirq(struct d
>  			pci_dev->bus->self->skip_bus_pm = true;
>  	}
>  
> -	if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) {
> +	if (pci_dev->skip_bus_pm && pm_suspend_no_platform()) {
>  		dev_dbg(dev, "PCI PM: Skipped\n");
>  		goto Fixup;
>  	}
> @@ -925,10 +925,10 @@ static int pci_pm_resume_noirq(struct de
>  	/*
>  	 * In the suspend-to-idle case, devices left in D0 during suspend will
>  	 * stay in D0, so it is not necessary to restore or update their
> -	 * configuration here and attempting to put them into D0 again may
> -	 * confuse some firmware, so avoid doing that.
> +	 * configuration here and attempting to put them into D0 again is
> +	 * pointless, so avoid doing that.
>  	 */
> -	if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware())
> +	if (!(pci_dev->skip_bus_pm && pm_suspend_no_platform()))
>  		pci_pm_default_resume_early(pci_dev);
>  
>  	pci_fixup_device(pci_fixup_resume_early, pci_dev);

I can confirm that above works for me. So ...

Tested-by: Jon Hunter <jonathanh@nvidia.com>

This looks better ...

[   52.545820] PM: suspend entry (deep)
[   52.549547] Filesystems sync: 0.000 seconds
[   52.553966] Freezing user space processes ... (elapsed 0.001 seconds) done.
[   52.562375] OOM killer disabled.
[   52.565684] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[   52.574426] printk: Suspending console(s) (use no_console_suspend to debug)
[   52.590255] r8169 0000:01:00.0 eth0: Link is Down
[   52.590483] pci_generic_config_write32: 22 callbacks suppressed
[   52.590488] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x9c may corrupt adjacent RW1C bits
[   52.794091] r8169 0000:01:00.0: PCI PM: Suspend power state: D3hot
[   52.794128] pcieport 0000:00:02.0: PCI PM: Suspend power state: D0
[   52.805674] Disabling non-boot CPUs ...
[   52.809257] Entering suspend state LP1
[   52.809284] Enabling non-boot CPUs ...
[   52.810184] CPU1 is up
[   52.810973] CPU2 is up
[   52.811819] CPU3 is up
[   52.822259] tegra-pcie 1003000.pcie: probing port 1, using 1 lanes
[   52.840085] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x4c may corrupt adjacent RW1C bits
[   52.840096] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x88 may corrupt adjacent RW1C bits
[   52.840101] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x90 may corrupt adjacent RW1C bits
[   52.840106] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x98 may corrupt adjacent RW1C bits
[   52.840111] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x9c may corrupt adjacent RW1C bits
[   52.840116] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0xa8 may corrupt adjacent RW1C bits
[   52.840121] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0xb0 may corrupt adjacent RW1C bits
[   52.840155] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x52 may corrupt adjacent RW1C bits
[   52.840160] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x52 may corrupt adjacent RW1C bits
[   52.840184] pcieport 0000:00:02.0: nv_msi_ht_cap_quirk didn't locate host bridge
[   52.864252] tegra-pcie 1003000.pcie: Slot present pin change, signature: 00000004
[   53.024171] r8169 0000:01:00.0 eth0: Link is Down
[   53.376438] ata1: SATA link down (SStatus 0 SControl 300)
[   55.881131] r8169 0000:01:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx
[   56.012154] OOM killer enabled.
[   56.015295] Restarting tasks ... done.
[   56.019415] PM: suspend exit
[   56.045929] PM: suspend entry (deep)
[   56.049565] Filesystems sync: 0.000 seconds
[   56.053906] Freezing user space processes ... (elapsed 0.001 seconds) done.
[   56.062205] OOM killer disabled.
[   56.065462] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[   56.074193] printk: Suspending console(s) (use no_console_suspend to debug)
[   56.096375] r8169 0000:01:00.0 eth0: Link is Down
[   56.304070] r8169 0000:01:00.0: PCI PM: Suspend power state: D3hot
[   56.304111] pcieport 0000:00:02.0: PCI PM: Suspend power state: D0
[   56.314134] tegra-pcie 1003000.pcie: PME Ack is not received on port: 1
[   56.325777] Disabling non-boot CPUs ...
[   56.328540] Entering suspend state LP1
[   56.328571] Enabling non-boot CPUs ...
[   56.329687] CPU1 is up
[   56.330694] CPU2 is up
[   56.331772] CPU3 is up
[   56.332396] tegra-pcie 1003000.pcie: probing port 1, using 1 lanes
[   56.350134] pcieport 0000:00:02.0: nv_msi_ht_cap_quirk didn't locate host bridge
[   56.374241] tegra-pcie 1003000.pcie: Slot present pin change, signature: 00000004
[   56.534158] r8169 0000:01:00.0 eth0: Link is Down
[   56.886516] ata1: SATA link down (SStatus 0 SControl 300)
[   59.417895] OOM killer enabled.
[   59.421025] Restarting tasks ... done.
[   59.425305] PM: suspend exit
[   60.756040] r8169 0000:01:00.0 eth0: Link is Up - 1Gbps/Full - flow control rx/tx

Thanks!
Jon

-- 
nvpublic

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Rafael J. Wysocki]

On Tue, Jun 25, 2019 at 1:09 AM Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>
> On Tuesday, June 25, 2019 12:20:26 AM CEST Rafael J. Wysocki wrote:
> > On Mon, Jun 24, 2019 at 11:37 PM Rafael J. Wysocki <rafael@kernel.org> wrote:
> > >
> > > On Mon, Jun 24, 2019 at 2:43 PM Jon Hunter <jonathanh@nvidia.com> wrote:
> > > >
> > > > Hi Rafael,
> > > >
> > > > On 13/06/2019 22:59, Rafael J. Wysocki wrote:
> > > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > >
> > > > > Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> > > > > attempted to avoid a problem with devices whose drivers want them to
> > > > > stay in D0 over suspend-to-idle and resume, but it did not go as far
> > > > > as it should with that.
> > > > >
> > > > > Namely, first of all, the power state of a PCI bridge with a
> > > > > downstream device in D0 must be D0 (based on the PCI PM spec r1.2,
> > > > > sec 6, table 6-1, if the bridge is not in D0, there can be no PCI
> > > > > transactions on its secondary bus), but that is not actively enforced
> > > > > during system-wide PM transitions, so use the skip_bus_pm flag
> > > > > introduced by commit d491f2b75237 for that.
> > > > >
> > > > > Second, the configuration of devices left in D0 (whatever the reason)
> > > > > during suspend-to-idle need not be changed and attempting to put them
> > > > > into D0 again by force is pointless, so explicitly avoid doing that.
> > > > >
> > > > > Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
> > > > > Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > > > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > > > Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> > > >
> > > > I have noticed a regression in both the mainline and -next branches on
> > > > one of our boards when testing suspend. The bisect is point to this
> > > > commit and reverting on top of mainline does fix the problem. So far I
> > > > have not looked at this in close detail but kernel log is showing ...
> > >
> > > Can you please collect a log like that, but with dynamic debug in
> > > pci-driver.c enabled?
> > >
> > > Note that reverting this commit is rather out of the question, so we
> > > need to get to the bottom of the failure.
> >
> > I suspect that there is a problem with the pm_suspend_via_firmware()
> > check which returns 'false' on the affected board, but the platform
> > actually removes power from devices left in D0 during suspend.
> >
> > I guess it would be more appropriate to check something like
> > pm_suspend_no_platform() which would return 'true' in the
> > suspend-to-idle patch w/ ACPI.
>
> So I wonder if the patch below makes any difference?

Mika, can you please test this one in combination with the other
changes we've been working on?

I really don't expect to see problems, but just to be sure ...

> ---
>  drivers/pci/pci-driver.c |    8 ++++----
>  include/linux/suspend.h  |   26 ++++++++++++++++++++++++--
>  kernel/power/suspend.c   |    3 +++
>  3 files changed, 31 insertions(+), 6 deletions(-)
>
> Index: linux-pm/include/linux/suspend.h
> ===================================================================
> --- linux-pm.orig/include/linux/suspend.h
> +++ linux-pm/include/linux/suspend.h
> @@ -209,8 +209,9 @@ extern int suspend_valid_only_mem(suspen
>
>  extern unsigned int pm_suspend_global_flags;
>
> -#define PM_SUSPEND_FLAG_FW_SUSPEND     (1 << 0)
> -#define PM_SUSPEND_FLAG_FW_RESUME      (1 << 1)
> +#define PM_SUSPEND_FLAG_FW_SUSPEND     BIT(0)
> +#define PM_SUSPEND_FLAG_FW_RESUME      BIT(1)
> +#define PM_SUSPEND_FLAG_NO_PLATFORM    BIT(2)
>
>  static inline void pm_suspend_clear_flags(void)
>  {
> @@ -227,6 +228,11 @@ static inline void pm_set_resume_via_fir
>         pm_suspend_global_flags |= PM_SUSPEND_FLAG_FW_RESUME;
>  }
>
> +static inline void pm_set_suspend_no_platform(void)
> +{
> +       pm_suspend_global_flags |= PM_SUSPEND_FLAG_NO_PLATFORM;
> +}
> +
>  /**
>   * pm_suspend_via_firmware - Check if platform firmware will suspend the system.
>   *
> @@ -268,6 +274,22 @@ static inline bool pm_resume_via_firmwar
>         return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_FW_RESUME);
>  }
>
> +/**
> + * pm_suspend_no_platform - Check if platform may change device power states.
> + *
> + * To be called during system-wide power management transitions to sleep states
> + * or during the subsequent system-wide transitions back to the working state.
> + *
> + * Return 'true' if the power states of devices remain under full control of the
> + * kernel throughout the system-wide suspend and resume cycle in progress (that
> + * is, if a device is put into a certain power state during suspend, it can be
> + * expected to remain in that state during resume).
> + */
> +static inline bool pm_suspend_no_platform(void)
> +{
> +       return !!(pm_suspend_global_flags & PM_SUSPEND_FLAG_NO_PLATFORM);
> +}
> +
>  /* Suspend-to-idle state machnine. */
>  enum s2idle_states {
>         S2IDLE_STATE_NONE,      /* Not suspended/suspending. */
> Index: linux-pm/kernel/power/suspend.c
> ===================================================================
> --- linux-pm.orig/kernel/power/suspend.c
> +++ linux-pm/kernel/power/suspend.c
> @@ -493,6 +493,9 @@ int suspend_devices_and_enter(suspend_st
>
>         pm_suspend_target_state = state;
>
> +       if (state == PM_SUSPEND_TO_IDLE)
> +               pm_set_suspend_no_platform();
> +
>         error = platform_suspend_begin(state);
>         if (error)
>                 goto Close;
> Index: linux-pm/drivers/pci/pci-driver.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-driver.c
> +++ linux-pm/drivers/pci/pci-driver.c
> @@ -870,7 +870,7 @@ static int pci_pm_suspend_noirq(struct d
>                         pci_dev->bus->self->skip_bus_pm = true;
>         }
>
> -       if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) {
> +       if (pci_dev->skip_bus_pm && pm_suspend_no_platform()) {
>                 dev_dbg(dev, "PCI PM: Skipped\n");
>                 goto Fixup;
>         }
> @@ -925,10 +925,10 @@ static int pci_pm_resume_noirq(struct de
>         /*
>          * In the suspend-to-idle case, devices left in D0 during suspend will
>          * stay in D0, so it is not necessary to restore or update their
> -        * configuration here and attempting to put them into D0 again may
> -        * confuse some firmware, so avoid doing that.
> +        * configuration here and attempting to put them into D0 again is
> +        * pointless, so avoid doing that.
>          */
> -       if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware())
> +       if (!(pci_dev->skip_bus_pm && pm_suspend_no_platform()))
>                 pci_pm_default_resume_early(pci_dev);
>
>         pci_fixup_device(pci_fixup_resume_early, pci_dev);
>
>
>

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Mika Westerberg]

On Tue, Jun 25, 2019 at 06:23:46PM +0200, Rafael J. Wysocki wrote:
> > So I wonder if the patch below makes any difference?
> 
> Mika, can you please test this one in combination with the other
> changes we've been working on?

Sure, I'll give it a try shortly.

Re: [PATCH v2] PCI: PM: Skip devices in D0 for suspend-to-idle

[Jon Hunter]

On 24/06/2019 22:37, Rafael J. Wysocki wrote:
> On Mon, Jun 24, 2019 at 2:43 PM Jon Hunter <jonathanh@nvidia.com> wrote:
>>
>> Hi Rafael,
>>
>> On 13/06/2019 22:59, Rafael J. Wysocki wrote:
>>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>
>>> Commit d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
>>> attempted to avoid a problem with devices whose drivers want them to
>>> stay in D0 over suspend-to-idle and resume, but it did not go as far
>>> as it should with that.
>>>
>>> Namely, first of all, the power state of a PCI bridge with a
>>> downstream device in D0 must be D0 (based on the PCI PM spec r1.2,
>>> sec 6, table 6-1, if the bridge is not in D0, there can be no PCI
>>> transactions on its secondary bus), but that is not actively enforced
>>> during system-wide PM transitions, so use the skip_bus_pm flag
>>> introduced by commit d491f2b75237 for that.
>>>
>>> Second, the configuration of devices left in D0 (whatever the reason)
>>> during suspend-to-idle need not be changed and attempting to put them
>>> into D0 again by force is pointless, so explicitly avoid doing that.
>>>
>>> Fixes: d491f2b75237 ("PCI: PM: Avoid possible suspend-to-idle issue")
>>> Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>>> Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>>
>> I have noticed a regression in both the mainline and -next branches on
>> one of our boards when testing suspend. The bisect is point to this
>> commit and reverting on top of mainline does fix the problem. So far I
>> have not looked at this in close detail but kernel log is showing ...
> 
> Can you please collect a log like that, but with dynamic debug in
> pci-driver.c enabled?

Yes, here you go ...

[   52.939258] PM: suspend entry (deep)
[   52.942963] Filesystems sync: 0.000 seconds
[   52.947596] Freezing user space processes ... (elapsed 0.001 seconds) done.
[   52.956145] OOM killer disabled.
[   52.959371] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[   52.968088] printk: Suspending console(s) (use no_console_suspend to debug)
[   52.992168] r8169 0000:01:00.0 eth0: Link is Down
[   52.992245] pci_generic_config_write32: 22 callbacks suppressed
[   52.992250] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x9c may corrupt adjacent RW1C bits
[   53.204186] r8169 0000:01:00.0: PCI PM: Suspend power state: D3hot
[   53.204221] pcieport 0000:00:02.0: PCI PM: Suspend power state: D0
[   53.204224] pcieport 0000:00:02.0: PCI PM: Skipped
[   53.215716] Disabling non-boot CPUs ...
[   53.218833] Entering suspend state LP1
[   53.218860] Enabling non-boot CPUs ...
[   53.219731] CPU1 is up
[   53.220482] CPU2 is up
[   53.221289] CPU3 is up
[   53.221850] tegra-pcie 1003000.pcie: probing port 1, using 1 lanes
[   53.239925] pcieport 0000:00:02.0: nv_msi_ht_cap_quirk didn't locate host bridge
[   53.264145] r8169 0000:01:00.0: Refused to change power state, currently in D3
[   53.326969] tegra-pcie 1003000.pcie: Slot present pin change, signature: 00000004
[   53.326975] tegra-pcie 1003000.pcie: Response decoding error, signature: 10010045
[   53.326978] tegra-pcie 1003000.pcie:   FPCI address: fe10010044
[   53.327091] tegra-pcie 1003000.pcie: Response decoding error, signature: 2000000c
[   53.327095] tegra-pcie 1003000.pcie:   FPCI address:   2000000c
[   53.327099] tegra-pcie 1003000.pcie: Response decoding error, signature: 20000001
[   53.327102] tegra-pcie 1003000.pcie:   FPCI address:   20000000
[   53.347944] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x88 may corrupt adjacent RW1C bits
[   53.347955] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x90 may corrupt adjacent RW1C bits
[   53.347962] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x98 may corrupt adjacent RW1C bits
[   53.347969] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x9c may corrupt adjacent RW1C bits
[   53.347977] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0xa8 may corrupt adjacent RW1C bits
[   53.347984] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0xb0 may corrupt adjacent RW1C bits
[   53.348025] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x52 may corrupt adjacent RW1C bits
[   53.348033] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x52 may corrupt adjacent RW1C bits
[   53.348043] pci_bus 0000:00: 2-byte config write to 0000:00:02.0 offset 0x5c may corrupt adjacent RW1C bits
[   53.358310] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   53.358592] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.394498] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.394789] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.395072] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.395352] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.395635] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.395919] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.396209] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.396488] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.396771] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.397055] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.397330] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.397608] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.397884] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.398162] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.398441] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.398721] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.399006] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.399295] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   53.399579] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.234501] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.234819] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.235104] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.235386] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.235403] Generic Realtek PHY r8169-100:00: Master/Slave resolution failed, maybe conflicting manual settings?
[   54.235406] ------------[ cut here ]------------
[   54.235416] WARNING: CPU: 3 PID: 112 at /home/jonathanh/workdir/tegra/mlt-linux_torvalds/kernel/drivers/net/phy/phy.c:735 phy_error+0x1c/0x54
[   54.235419] Modules linked in: ttm
[   54.235429] CPU: 3 PID: 112 Comm: kworker/3:1 Not tainted 5.2.0-rc6-dirty #3
[   54.235431] Hardware name: NVIDIA Tegra SoC (Flattened Device Tree)
[   54.235441] Workqueue: events_power_efficient phy_state_machine
[   54.235455] [<c0112244>] (unwind_backtrace) from [<c010cad8>] (show_stack+0x10/0x14)
[   54.235463] [<c010cad8>] (show_stack) from [<c0a606a4>] (dump_stack+0xb4/0xc8)
[   54.235471] [<c0a606a4>] (dump_stack) from [<c0123cbc>] (__warn+0xe0/0xf8)
[   54.235477] [<c0123cbc>] (__warn) from [<c0123dec>] (warn_slowpath_null+0x40/0x48)
[   54.235482] [<c0123dec>] (warn_slowpath_null) from [<c0617470>] (phy_error+0x1c/0x54)
[   54.235488] [<c0617470>] (phy_error) from [<c0618564>] (phy_state_machine+0x64/0x1c0)
[   54.235498] [<c0618564>] (phy_state_machine) from [<c013e744>] (process_one_work+0x204/0x578)
[   54.235503] [<c013e744>] (process_one_work) from [<c013f444>] (worker_thread+0x44/0x584)
[   54.235507] [<c013f444>] (worker_thread) from [<c01445d4>] (kthread+0x148/0x150)
[   54.235512] [<c01445d4>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
[   54.235515] Exception stack(0xe9ea1fb0 to 0xe9ea1ff8)
[   54.235518] 1fa0:                                     00000000 00000000 00000000 00000000
[   54.235522] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[   54.235525] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[   54.235528] ---[ end trace 772a7ce78ffff5e6 ]---
[   54.235551] r8169 0000:01:00.0 eth0: Link is Down
[   54.245804] r8169 0000:01:00.0 eth0: rtl_chipcmd_cond == 1 (loop: 100, delay: 100).
[   54.256058] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.266257] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.276454] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.286656] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.296860] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.307064] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.317263] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.327464] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.337660] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.347902] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.358102] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.368303] r8169 0000:01:00.0 eth0: rtl_eriar_cond == 1 (loop: 100, delay: 100).
[   54.369471] r8169 0000:01:00.0 eth0: rtl_ephyar_cond == 1 (loop: 100, delay: 10).
[   54.370637] r8169 0000:01:00.0 eth0: rtl_ephyar_cond == 1 (loop: 100, delay: 10).
[   54.371799] r8169 0000:01:00.0 eth0: rtl_ephyar_cond == 1 (loop: 100, delay: 10).
[   54.372961] r8169 0000:01:00.0 eth0: rtl_ephyar_cond == 1 (loop: 100, delay: 10).
[   54.373416] r8169 0000:01:00.0 eth0: rtl_ocp_gphy_cond == 1 (loop: 10, delay: 25).
[   54.716510] ata1: SATA link down (SStatus 0 SControl 300)
[   56.998780] OOM killer enabled.
[   57.001909] Restarting tasks ... done.
[   57.007392] PM: suspend exit
[   73.144767] nfs: server 192.168.99.1 not responding, still trying
[   77.624567] nfs: server 192.168.99.1 not responding, still trying

Cheers
Jon

-- 
nvpublic