* [PATCH] PM / s2idle: Clear the events_check_enabled flag
@ 2017-10-31 21:44 Rajat Jain
2017-11-06 11:13 ` Pavel Machek
0 siblings, 1 reply; 4+ messages in thread
From: Rajat Jain @ 2017-10-31 21:44 UTC (permalink / raw)
To: Rafael J. Wysocki, Pavel Machek, Len Brown, linux-pm,
linux-kernel, dtor, rajatxjain
Cc: Rajat Jain
Problem: This flag does not get cleared currently in the suspend or
resume path in the following cases:
* In case some driver's suspend routine returns an error.
* Successful s2idle case
* etc?
Why is this a problem: What happens is that the next suspend attempt
could fail even though the user did not enable the flag by writing to
/sys/power/wakeup_count. This is 1 use case how the issue can be seen
(but similar use case with driver suspend failure can be thought of):
1. Read /sys/power/wakeup_count
2. echo count > /sys/power/wakeup_count
3. echo freeze > /sys/power/wakeup_count
4. Let the system suspend, and wakeup the system using some wake source
that calls pm_wakeup_event() e.g. power button or something.
5. Note that the combined wakeup count would be incremented due
to the pm_wakeup_event() in the resume path.
6. After resuming the events_check_enabled flag is still set.
At this point if the user attempts to freeze again (without writing to
/sys/power/wakeup_count), the suspend would fail even though there has
been no wake event since the past resume.
What this patch does:
It moves the clearing of the flag to just before a resume is completed,
so that it is always cleared for the corner cases mentioned above.
Signed-off-by: Rajat Jain <rajatja@google.com>
---
kernel/power/suspend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index ccd2d20e6b06..0685c4499431 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
error = suspend_ops->enter(state);
trace_suspend_resume(TPS("machine_suspend"),
state, false);
- events_check_enabled = false;
} else if (*wakeup) {
error = -EBUSY;
}
@@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state)
pm_restore_gfp_mask();
Finish:
+ events_check_enabled = false;
pm_pr_dbg("Finishing wakeup.\n");
suspend_finish();
Unlock:
--
2.15.0.403.gc27cc4dac6-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] PM / s2idle: Clear the events_check_enabled flag
2017-10-31 21:44 [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
@ 2017-11-06 11:13 ` Pavel Machek
0 siblings, 0 replies; 4+ messages in thread
From: Pavel Machek @ 2017-11-06 11:13 UTC (permalink / raw)
To: Rajat Jain
Cc: Rafael J. Wysocki, Len Brown, linux-pm, linux-kernel, dtor, rajatxjain
[-- Attachment #1: Type: text/plain, Size: 1615 bytes --]
On Tue 2017-10-31 14:44:24, Rajat Jain wrote:
> Problem: This flag does not get cleared currently in the suspend or
> resume path in the following cases:
>
> * In case some driver's suspend routine returns an error.
> * Successful s2idle case
> * etc?
>
> Why is this a problem: What happens is that the next suspend attempt
> could fail even though the user did not enable the flag by writing to
> /sys/power/wakeup_count. This is 1 use case how the issue can be seen
> (but similar use case with driver suspend failure can be thought of):
>
> 1. Read /sys/power/wakeup_count
> 2. echo count > /sys/power/wakeup_count
> 3. echo freeze > /sys/power/wakeup_count
> 4. Let the system suspend, and wakeup the system using some wake source
> that calls pm_wakeup_event() e.g. power button or something.
> 5. Note that the combined wakeup count would be incremented due
> to the pm_wakeup_event() in the resume path.
> 6. After resuming the events_check_enabled flag is still set.
>
> At this point if the user attempts to freeze again (without writing to
> /sys/power/wakeup_count), the suspend would fail even though there has
> been no wake event since the past resume.
>
> What this patch does:
>
> It moves the clearing of the flag to just before a resume is completed,
> so that it is always cleared for the corner cases mentioned above.
>
> Signed-off-by: Rajat Jain <rajatja@google.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] pci/aspm: Remove CONFIG_PCIEASPM_DEBUG
@ 2018-05-08 23:01 Rajat Jain
2018-05-10 23:34 ` [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
0 siblings, 1 reply; 4+ messages in thread
From: Rajat Jain @ 2018-05-08 23:01 UTC (permalink / raw)
To: Bjorn Helgaas, Rajat Jain, Keith Busch, Vidya Sagar,
Philippe Ombredanne, Kees Cook, Gustavo A. R. Silva,
Ard Biesheuvel, Sinan Kaya, Frederick Lawler, linux-pci,
linux-kernel, mayurkumar.patel
Cc: rajatxjain
Currently, the linux kernel disables ASPM when a device is
removed from the kernel. But it is not enabled again when
a new device is added on that slot even if it was originally
enabled (by the BIOS) when the system booted up (assuming
POLICY_DEFAULT).
This was earlier discussed here:
https://www.spinics.net/lists/linux-pci/msg60212.html
And some suggestions from Bjorn here:
https://www.spinics.net/lists/linux-pci/msg60541.html
This patch picks up one of the suggestion, to remove the
CONFIG_PCIEASPM_DEBUG and thus make the code always
avilable. This provides control to userspace to control
ASPM on a per slot / device basis using sysfs interface.
Signed-off-by: Rajat Jain <rajatja@google.com>
---
drivers/pci/pci.h | 5 -----
drivers/pci/pcie/Kconfig | 8 --------
drivers/pci/pcie/aspm.c | 2 --
3 files changed, 15 deletions(-)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 023f7cf25bff..383d92a6b0fb 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -365,13 +365,8 @@ static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { }
static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { }
#endif
-#ifdef CONFIG_PCIEASPM_DEBUG
void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
-#else
-static inline void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev) { }
-static inline void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev) { }
-#endif
#ifdef CONFIG_PCIE_PTM
void pci_ptm_init(struct pci_dev *dev);
diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig
index b12e28b3d8f9..089b9f559d88 100644
--- a/drivers/pci/pcie/Kconfig
+++ b/drivers/pci/pcie/Kconfig
@@ -46,14 +46,6 @@ config PCIEASPM
When in doubt, say Y.
-config PCIEASPM_DEBUG
- bool "Debug PCI Express ASPM"
- depends on PCIEASPM
- default n
- help
- This enables PCI Express ASPM debug support. It will add per-device
- interface to control ASPM.
-
choice
prompt "Default ASPM policy"
default PCIEASPM_DEFAULT
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index c687c817b47d..8ffc13d42baa 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -1161,7 +1161,6 @@ static int pcie_aspm_get_policy(char *buffer, const struct kernel_param *kp)
module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
NULL, 0644);
-#ifdef CONFIG_PCIEASPM_DEBUG
static ssize_t link_state_show(struct device *dev,
struct device_attribute *attr,
char *buf)
@@ -1264,7 +1263,6 @@ void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
sysfs_remove_file_from_group(&pdev->dev.kobj,
&dev_attr_clk_ctl.attr, power_group);
}
-#endif
static int __init pcie_aspm_disable(char *str)
{
--
2.17.0.441.gb46fe60e1d-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] PM / s2idle: Clear the events_check_enabled flag
2018-05-08 23:01 [PATCH] pci/aspm: Remove CONFIG_PCIEASPM_DEBUG Rajat Jain
@ 2018-05-10 23:34 ` Rajat Jain
2018-05-10 23:36 ` Rajat Jain
0 siblings, 1 reply; 4+ messages in thread
From: Rajat Jain @ 2018-05-10 23:34 UTC (permalink / raw)
To: Rafael J. Wysocki, Pavel Machek, Len Brown, linux-pm,
linux-kernel, dtor, rajatxjain
Cc: Rajat Jain
Problem: This flag does not get cleared currently in the suspend or
resume path in the following cases:
* In case some driver's suspend routine returns an error.
* Successful s2idle case
* etc?
Why is this a problem: What happens is that the next suspend attempt
could fail even though the user did not enable the flag by writing to
/sys/power/wakeup_count. This is 1 use case how the issue can be seen
(but similar use case with driver suspend failure can be thought of):
1. Read /sys/power/wakeup_count
2. echo count > /sys/power/wakeup_count
3. echo freeze > /sys/power/wakeup_count
4. Let the system suspend, and wakeup the system using some wake source
that calls pm_wakeup_event() e.g. power button or something.
5. Note that the combined wakeup count would be incremented due
to the pm_wakeup_event() in the resume path.
6. After resuming the events_check_enabled flag is still set.
At this point if the user attempts to freeze again (without writing to
/sys/power/wakeup_count), the suspend would fail even though there has
been no wake event since the past resume.
What this patch does:
It moves the clearing of the flag to just before a resume is completed,
so that it is always cleared for the corner cases mentioned above.
Signed-off-by: Rajat Jain <rajatja@google.com>
---
kernel/power/suspend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index ccd2d20e6b06..0685c4499431 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
error = suspend_ops->enter(state);
trace_suspend_resume(TPS("machine_suspend"),
state, false);
- events_check_enabled = false;
} else if (*wakeup) {
error = -EBUSY;
}
@@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state)
pm_restore_gfp_mask();
Finish:
+ events_check_enabled = false;
pm_pr_dbg("Finishing wakeup.\n");
suspend_finish();
Unlock:
--
2.15.0.403.gc27cc4dac6-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] PM / s2idle: Clear the events_check_enabled flag
2018-05-10 23:34 ` [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
@ 2018-05-10 23:36 ` Rajat Jain
0 siblings, 0 replies; 4+ messages in thread
From: Rajat Jain @ 2018-05-10 23:36 UTC (permalink / raw)
To: Rafael J. Wysocki, Pavel Machek, Len Brown, Linux PM,
Linux Kernel Mailing List, Dmitry Torokhov, Rajat Jain
Cc: Rajat Jain
Sorry, please ignore, sent by mistake.
On Thu, May 10, 2018 at 4:34 PM, Rajat Jain <rajatja@google.com> wrote:
> Problem: This flag does not get cleared currently in the suspend or
> resume path in the following cases:
>
> * In case some driver's suspend routine returns an error.
> * Successful s2idle case
> * etc?
>
> Why is this a problem: What happens is that the next suspend attempt
> could fail even though the user did not enable the flag by writing to
> /sys/power/wakeup_count. This is 1 use case how the issue can be seen
> (but similar use case with driver suspend failure can be thought of):
>
> 1. Read /sys/power/wakeup_count
> 2. echo count > /sys/power/wakeup_count
> 3. echo freeze > /sys/power/wakeup_count
> 4. Let the system suspend, and wakeup the system using some wake source
> that calls pm_wakeup_event() e.g. power button or something.
> 5. Note that the combined wakeup count would be incremented due
> to the pm_wakeup_event() in the resume path.
> 6. After resuming the events_check_enabled flag is still set.
>
> At this point if the user attempts to freeze again (without writing to
> /sys/power/wakeup_count), the suspend would fail even though there has
> been no wake event since the past resume.
>
> What this patch does:
>
> It moves the clearing of the flag to just before a resume is completed,
> so that it is always cleared for the corner cases mentioned above.
>
> Signed-off-by: Rajat Jain <rajatja@google.com>
> ---
> kernel/power/suspend.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index ccd2d20e6b06..0685c4499431 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -437,7 +437,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup)
> error = suspend_ops->enter(state);
> trace_suspend_resume(TPS("machine_suspend"),
> state, false);
> - events_check_enabled = false;
> } else if (*wakeup) {
> error = -EBUSY;
> }
> @@ -582,6 +581,7 @@ static int enter_state(suspend_state_t state)
> pm_restore_gfp_mask();
>
> Finish:
> + events_check_enabled = false;
> pm_pr_dbg("Finishing wakeup.\n");
> suspend_finish();
> Unlock:
> --
> 2.15.0.403.gc27cc4dac6-goog
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-05-10 23:37 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-10-31 21:44 [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
2017-11-06 11:13 ` Pavel Machek
2018-05-08 23:01 [PATCH] pci/aspm: Remove CONFIG_PCIEASPM_DEBUG Rajat Jain
2018-05-10 23:34 ` [PATCH] PM / s2idle: Clear the events_check_enabled flag Rajat Jain
2018-05-10 23:36 ` Rajat Jain
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