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author | Vaibhav Hiremath <hiremath_vaibhav@projectara.com> | 2016-08-03 17:15:38 +0530 |
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committer | Greg Kroah-Hartman <gregkh@google.com> | 2016-08-03 15:43:51 +0200 |
commit | 8ef0b5383110977d81746cd0b09c3877d51c3a67 (patch) | |
tree | e401faaa6f7119157efc52da52ffb2eb0a59d09d /drivers/staging/greybus/arche-platform.c | |
parent | greybus: es2: rename USB vendor-request timeout define (diff) | |
download | linux-dev-8ef0b5383110977d81746cd0b09c3877d51c3a67.tar.xz linux-dev-8ef0b5383110977d81746cd0b09c3877d51c3a67.zip |
greybus: arche-platform: Reset SVC & APB only if turned off by SUSPEND_PREPARE
There is possible race condition in arche platform driver for
maintaining of ->state field, when shared with timesync driver.
Assume device booted fine, all connected modules have been enumerated
correctly. As part of suspend-resume operation we have pm_notifier
callback, where we turn off SVC & APB and coldboot on resume.
In the process of resume, all modules gets enumerated again, and
timesync driver does come into picture everytime.
So when timesync driver requests arche-platform to change the state
to TIMESYNC and in the middle of sync operation, if suspend gets
triggered, then execution lands into arche-platform->pm_notifier callback,
leading to race condition in the driver, where it checks for (state != ACTIVE)
in PM_SUSPEND_PREPARE and returns, but in PM_POST_SUSPEND it just simply
coldboots SVC & APB, which would inbalance all resources (including IRQ).
So we need a add check in PM_POST_SUSPEND, to make sure that, we only
coldboot devices if they are in to off state,
i.e. if (state != OFF) then return.
Testing Done: Done regressive suspend/resume testing on EVT2 platform.
Note that, I some time hit issue.
Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Diffstat (limited to 'drivers/staging/greybus/arche-platform.c')
-rw-r--r-- | drivers/staging/greybus/arche-platform.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/staging/greybus/arche-platform.c b/drivers/staging/greybus/arche-platform.c index cbe8bdcabceb..adec1fdcb5bb 100644 --- a/drivers/staging/greybus/arche-platform.c +++ b/drivers/staging/greybus/arche-platform.c @@ -548,6 +548,9 @@ static int arche_platform_pm_notifier(struct notifier_block *notifier, arche_platform_poweroff_seq(arche_pdata); break; case PM_POST_SUSPEND: + if (arche_pdata->state != ARCHE_PLATFORM_STATE_OFF) + break; + arche_platform_wd_irq_en(arche_pdata); arche_platform_coldboot_seq(arche_pdata); break; |