[2/5] memstick: Prevent memstick host from getting runtime suspended during card detection
From: Kai-Heng Feng <hidden>
Date: 2018-07-23 10:28:06
Also in:
lkml
Subsystem:
sony memorystick subsystem, the rest · Maintainers:
Maxim Levitsky, Alex Dubov, Ulf Hansson, Linus Torvalds
Possibly related (same subject, not in this thread)
- 2018-07-31 · [PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection · Kai-Heng Feng <hidden>
- 2018-07-26 · Re: [PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection · Kai-Heng Feng <hidden>
- 2018-07-25 · Re: [PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection · Alan Stern <stern@rowland.harvard.edu>
- 2018-07-25 · [PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection · Kai-Heng Feng <hidden>
We can use MEMSTICK_POWER_{ON,OFF} along with pm_runtime_{get,put}
helpers to let memstick host support runtime pm.
There's a small window between memstick_detect_change() and its queued
work, memstick_check(). In this window the rpm count may go down to zero
before the memstick host powers on, so the host can be inadvertently
suspended.
Increment rpm count before calling memstick_check(), and decrement rpm
count afterward, as now we are sure the memstick host should be
suspended or not.
Signed-off-by: Kai-Heng Feng <redacted>
---
drivers/memstick/core/memstick.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c
index 76382c858c35..944fe0c93fa7 100644
--- a/drivers/memstick/core/memstick.c
+++ b/drivers/memstick/core/memstick.c@@ -18,6 +18,7 @@ #include <linux/delay.h> #include <linux/slab.h> #include <linux/module.h> +#include <linux/pm_runtime.h> #define DRIVER_NAME "memstick"
@@ -209,6 +210,7 @@ static int memstick_dummy_check(struct memstick_dev *card) */ void memstick_detect_change(struct memstick_host *host) { + pm_runtime_get_noresume(host->dev.parent); queue_work(workqueue, &host->media_checker); } EXPORT_SYMBOL(memstick_detect_change);
@@ -479,6 +481,8 @@ static void memstick_check(struct work_struct *work) host->set_param(host, MEMSTICK_POWER, MEMSTICK_POWER_OFF); mutex_unlock(&host->lock); + + pm_runtime_put_noidle(host->dev.parent); dev_dbg(&host->dev, "memstick_check finished\n"); }