[PATCH 0/5 v2] Keep rtsx_usb suspended when there's no card

[PATCH 0/5 v2] Keep rtsx_usb suspended when there's no card

[Kai-Heng Feng]

Hi,

This is based on Ulf's work [1] [2].

This patch series can keep rtsx_usb suspended, to save ~0.5W on Intel
platforms and ~1.5W on AMD platforms.

[1] https://patchwork.kernel.org/patch/10440583/
[2] https://patchwork.kernel.org/patch/10445725/

Kai-Heng Feng (5):
  misc: rtsx_usb: Use USB remote wakeup signaling for card insertion
    detection
  memstick: Prevent memstick host from getting runtime suspended during
    card detection
  memstick: rtsx_usb_ms: Use ms_dev() helper
  memstick: rtsx_usb_ms: Support runtime power management
  misc: rtsx_usb: / memstick: rtsx_usb_ms: Avoid long delay before
    system suspend

v2: Sends to linux-usb and LKML.

 drivers/memstick/core/memstick.c    |   4 +
 drivers/memstick/host/rtsx_usb_ms.c | 145 ++++++++++++++++------------
 drivers/misc/cardreader/rtsx_usb.c  |  14 +++
 3 files changed, 99 insertions(+), 64 deletions(-)

-- 
2.17.1

[PATCH 1/5] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection

[Kai-Heng Feng]

Although rtsx_usb doesn't support card removal detection, card insertion
will resume rtsx_usb by USB remote wakeup signaling.

When rtsx_usb gets resumed, also resumes its child devices,
rtsx_usb_sdmmc and rtsx_usb_ms, to notify them there's a card in its
slot.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/misc/cardreader/rtsx_usb.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
index b97903ff1a72..fed83453e5c5 100644
--- a/drivers/misc/cardreader/rtsx_usb.c
+++ b/drivers/misc/cardreader/rtsx_usb.c
@@ -723,8 +723,20 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
 	return 0;
 }
 
+static int rtsx_usb_resume_child(struct device *dev, void *data)
+{
+	/* No need to wake up self again */
+	if (dev == data)
+		return 0;
+
+	dev_dbg(dev, "%s called\n", __func__);
+	pm_request_resume(dev);
+	return 0;
+}
+
 static int rtsx_usb_resume(struct usb_interface *intf)
 {
+	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
 	return 0;
 }
 
@@ -734,6 +746,7 @@ static int rtsx_usb_reset_resume(struct usb_interface *intf)
 		(struct rtsx_ucr *)usb_get_intfdata(intf);
 
 	rtsx_usb_reset_chip(ucr);
+	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
 	return 0;
 }
 
-- 
2.17.1

[1/5] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection

[Kai-Heng Feng]

Although rtsx_usb doesn't support card removal detection, card insertion
will resume rtsx_usb by USB remote wakeup signaling.

When rtsx_usb gets resumed, also resumes its child devices,
rtsx_usb_sdmmc and rtsx_usb_ms, to notify them there's a card in its
slot.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/misc/cardreader/rtsx_usb.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
index b97903ff1a72..fed83453e5c5 100644
--- a/drivers/misc/cardreader/rtsx_usb.c
+++ b/drivers/misc/cardreader/rtsx_usb.c
@@ -723,8 +723,20 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
 	return 0;
 }
 
+static int rtsx_usb_resume_child(struct device *dev, void *data)
+{
+	/* No need to wake up self again */
+	if (dev == data)
+		return 0;
+
+	dev_dbg(dev, "%s called\n", __func__);
+	pm_request_resume(dev);
+	return 0;
+}
+
 static int rtsx_usb_resume(struct usb_interface *intf)
 {
+	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
 	return 0;
 }
 
@@ -734,6 +746,7 @@ static int rtsx_usb_reset_resume(struct usb_interface *intf)
 		(struct rtsx_ucr *)usb_get_intfdata(intf);
 
 	rtsx_usb_reset_chip(ucr);
+	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
 	return 0;
 }
 

[PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection

[Kai-Heng Feng]

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 <kai.heng.feng@canonical.com>
---
 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");
 }
 
-- 
2.17.1

[2/5] memstick: Prevent memstick host from getting runtime suspended during card detection

[Kai-Heng Feng]

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 <kai.heng.feng@canonical.com>
---
 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");
 }
 

[PATCH 3/5] memstick: rtsx_usb_ms: Use ms_dev() helper

[Kai-Heng Feng]

Use ms_dev() helper for consistency.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index 4f64563df7de..d56f0863653f 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -807,7 +807,7 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	if (pm_runtime_active(ms_dev(host)))
 		pm_runtime_put(ms_dev(host));
 
-	pm_runtime_disable(&pdev->dev);
+	pm_runtime_disable(ms_dev(host));
 	platform_set_drvdata(pdev, NULL);
 
 	dev_dbg(&(pdev->dev),
-- 
2.17.1

[3/5] memstick: rtsx_usb_ms: Use ms_dev() helper

[Kai-Heng Feng]

Use ms_dev() helper for consistency.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index 4f64563df7de..d56f0863653f 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -807,7 +807,7 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	if (pm_runtime_active(ms_dev(host)))
 		pm_runtime_put(ms_dev(host));
 
-	pm_runtime_disable(&pdev->dev);
+	pm_runtime_disable(ms_dev(host));
 	platform_set_drvdata(pdev, NULL);
 
 	dev_dbg(&(pdev->dev),

[PATCH 4/5] memstick: rtsx_usb_ms: Support runtime power management

[Kai-Heng Feng]

In order to let host's parent device, rtsx_usb, to use USB remote wake
up signaling to do card detection, it needs to be suspended. Hence it's
necessary to add runtime PM support for the memstick host.

To keep memstick host stays suspended when it's not in use, convert the
card detection function from kthread to delayed_work, which can be
scheduled when the host is resumed and can be canceled when the host is
suspended.

Use an idle function check if there's no card and the power mode is
MEMSTICK_POWER_OFF. If both criteria are met, put the device to suspend.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 139 +++++++++++++++-------------
 1 file changed, 76 insertions(+), 63 deletions(-)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index d56f0863653f..622497554a5a 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -40,15 +40,14 @@ struct rtsx_usb_ms {
 
 	struct mutex		host_mutex;
 	struct work_struct	handle_req;
-
-	struct task_struct	*detect_ms;
-	struct completion	detect_ms_exit;
+	struct delayed_work	poll_card;
 
 	u8			ssc_depth;
 	unsigned int		clock;
 	int			power_mode;
 	unsigned char           ifmode;
 	bool			eject;
+	bool			suspend;
 };
 
 static inline struct device *ms_dev(struct rtsx_usb_ms *host)
@@ -524,7 +523,7 @@ static void rtsx_usb_ms_handle_req(struct work_struct *work)
 	int rc;
 
 	if (!host->req) {
-		pm_runtime_get_sync(ms_dev(host));
+		pm_runtime_get_noresume(ms_dev(host));
 		do {
 			rc = memstick_next_req(msh, &host->req);
 			dev_dbg(ms_dev(host), "next req %d\n", rc);
@@ -545,7 +544,7 @@ static void rtsx_usb_ms_handle_req(struct work_struct *work)
 						host->req->error);
 			}
 		} while (!rc);
-		pm_runtime_put(ms_dev(host));
+		pm_runtime_put_noidle(ms_dev(host));
 	}
 
 }
@@ -572,7 +571,7 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	dev_dbg(ms_dev(host), "%s: param = %d, value = %d\n",
 			__func__, param, value);
 
-	pm_runtime_get_sync(ms_dev(host));
+	pm_runtime_get_noresume(ms_dev(host));
 	mutex_lock(&ucr->dev_mutex);
 
 	err = rtsx_usb_card_exclusive_check(ucr, RTSX_USB_MS_CARD);
@@ -585,14 +584,14 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 			break;
 
 		if (value == MEMSTICK_POWER_ON) {
-			pm_runtime_get_sync(ms_dev(host));
+			pm_runtime_get_noresume(ms_dev(host));
 			err = ms_power_on(host);
+			if (err)
+				pm_runtime_put_noidle(ms_dev(host));
 		} else if (value == MEMSTICK_POWER_OFF) {
 			err = ms_power_off(host);
-			if (host->msh->card)
+			if (!err)
 				pm_runtime_put_noidle(ms_dev(host));
-			else
-				pm_runtime_put(ms_dev(host));
 		} else
 			err = -EINVAL;
 		if (!err)
@@ -638,7 +637,7 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	}
 out:
 	mutex_unlock(&ucr->dev_mutex);
-	pm_runtime_put(ms_dev(host));
+	pm_runtime_put_noidle(ms_dev(host));
 
 	/* power-on delay */
 	if (param == MEMSTICK_POWER && value == MEMSTICK_POWER_ON)
@@ -648,19 +647,21 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	return err;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int rtsx_usb_ms_suspend(struct device *dev)
+#ifdef CONFIG_PM
+static int rtsx_usb_ms_runtime_suspend(struct device *dev)
 {
 	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
 	struct memstick_host *msh = host->msh;
 
 	dev_dbg(ms_dev(host), "--> %s\n", __func__);
 
+	host->suspend = 1;
 	memstick_suspend_host(msh);
+
 	return 0;
 }
 
-static int rtsx_usb_ms_resume(struct device *dev)
+static int rtsx_usb_ms_runtime_resume(struct device *dev)
 {
 	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
 	struct memstick_host *msh = host->msh;
@@ -668,55 +669,72 @@ static int rtsx_usb_ms_resume(struct device *dev)
 	dev_dbg(ms_dev(host), "--> %s\n", __func__);
 
 	memstick_resume_host(msh);
+	host->suspend = 0;
+	schedule_delayed_work(&host->poll_card, 100);
+
 	return 0;
 }
-#endif /* CONFIG_PM_SLEEP */
 
-/*
- * Thread function of ms card slot detection. The thread starts right after
- * successful host addition. It stops while the driver removal function sets
- * host->eject true.
- */
-static int rtsx_usb_detect_ms_card(void *__host)
+static int rtsx_usb_ms_runtime_idle(struct device *dev)
+{
+	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
+
+	dev_dbg(ms_dev(host), "--> %s\n", __func__);
+
+	if (!host->msh->card && host->power_mode == MEMSTICK_POWER_OFF) {
+		pm_schedule_suspend(dev, 0);
+		return 0;
+	}
+
+	return -EAGAIN;
+}
+
+static const UNIVERSAL_DEV_PM_OPS(rtsx_usb_ms_pm_ops,
+		rtsx_usb_ms_runtime_suspend, rtsx_usb_ms_runtime_resume,
+		rtsx_usb_ms_runtime_idle);
+#endif /* CONFIG_PM */
+
+static void rtsx_usb_ms_poll_card(struct work_struct *work)
 {
-	struct rtsx_usb_ms *host = (struct rtsx_usb_ms *)__host;
+	struct rtsx_usb_ms *host = container_of(work, struct rtsx_usb_ms,
+			poll_card.work);
 	struct rtsx_ucr *ucr = host->ucr;
-	u8 val = 0;
 	int err;
+	u8 val;
 
-	for (;;) {
-		pm_runtime_get_sync(ms_dev(host));
-		mutex_lock(&ucr->dev_mutex);
+	dev_dbg(ms_dev(host), "--> %s\n", __func__);
 
-		/* Check pending MS card changes */
-		err = rtsx_usb_read_register(ucr, CARD_INT_PEND, &val);
-		if (err) {
-			mutex_unlock(&ucr->dev_mutex);
-			goto poll_again;
-		}
+	if (host->eject || host->suspend)
+		return;
 
-		/* Clear the pending */
-		rtsx_usb_write_register(ucr, CARD_INT_PEND,
-				XD_INT | MS_INT | SD_INT,
-				XD_INT | MS_INT | SD_INT);
+	pm_runtime_get_noresume(ms_dev(host));
+	mutex_lock(&ucr->dev_mutex);
 
+	/* Check pending MS card changes */
+	err = rtsx_usb_read_register(ucr, CARD_INT_PEND, &val);
+	if (err) {
 		mutex_unlock(&ucr->dev_mutex);
+		goto poll_again;
+	}
 
-		if (val & MS_INT) {
-			dev_dbg(ms_dev(host), "MS slot change detected\n");
-			memstick_detect_change(host->msh);
-		}
+	/* Clear the pending */
+	rtsx_usb_write_register(ucr, CARD_INT_PEND,
+			XD_INT | MS_INT | SD_INT,
+			XD_INT | MS_INT | SD_INT);
 
-poll_again:
-		pm_runtime_put(ms_dev(host));
-		if (host->eject)
-			break;
+	mutex_unlock(&ucr->dev_mutex);
+	pm_runtime_put_noidle(ms_dev(host));
 
-		schedule_timeout_idle(HZ);
+	if (val & MS_INT) {
+		dev_dbg(ms_dev(host), "MS slot change detected\n");
+		memstick_detect_change(host->msh);
 	}
 
-	complete(&host->detect_ms_exit);
-	return 0;
+	pm_runtime_idle(ms_dev(host));
+
+poll_again:
+	if (!host->eject && !host->suspend)
+		schedule_delayed_work(&host->poll_card, 100);
 }
 
 static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
@@ -742,31 +760,27 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
 	host->msh = msh;
 	host->pdev = pdev;
 	host->power_mode = MEMSTICK_POWER_OFF;
+	host->eject = 0;
 	platform_set_drvdata(pdev, host);
 
 	mutex_init(&host->host_mutex);
 	INIT_WORK(&host->handle_req, rtsx_usb_ms_handle_req);
 
-	init_completion(&host->detect_ms_exit);
-	host->detect_ms = kthread_create(rtsx_usb_detect_ms_card, host,
-			"rtsx_usb_ms_%d", pdev->id);
-	if (IS_ERR(host->detect_ms)) {
-		dev_dbg(&(pdev->dev),
-				"Unable to create polling thread.\n");
-		err = PTR_ERR(host->detect_ms);
-		goto err_out;
-	}
+	INIT_DELAYED_WORK(&host->poll_card, rtsx_usb_ms_poll_card);
 
 	msh->request = rtsx_usb_ms_request;
 	msh->set_param = rtsx_usb_ms_set_param;
 	msh->caps = MEMSTICK_CAP_PAR4;
 
-	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_active(ms_dev(host));
+	pm_runtime_enable(ms_dev(host));
+
 	err = memstick_add_host(msh);
 	if (err)
 		goto err_out;
 
-	wake_up_process(host->detect_ms);
+	schedule_delayed_work(&host->poll_card, 100);
+
 	return 0;
 err_out:
 	memstick_free_host(msh);
@@ -780,8 +794,9 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	int err;
 
 	msh = host->msh;
-	host->eject = true;
+	host->eject = 1;
 	cancel_work_sync(&host->handle_req);
+	cancel_delayed_work_sync(&host->poll_card);
 
 	mutex_lock(&host->host_mutex);
 	if (host->req) {
@@ -797,7 +812,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	}
 	mutex_unlock(&host->host_mutex);
 
-	wait_for_completion(&host->detect_ms_exit);
 	memstick_remove_host(msh);
 	memstick_free_host(msh);
 
@@ -816,9 +830,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(rtsx_usb_ms_pm_ops,
-		rtsx_usb_ms_suspend, rtsx_usb_ms_resume);
-
 static struct platform_device_id rtsx_usb_ms_ids[] = {
 	{
 		.name = "rtsx_usb_ms",
@@ -834,7 +845,9 @@ static struct platform_driver rtsx_usb_ms_driver = {
 	.id_table       = rtsx_usb_ms_ids,
 	.driver		= {
 		.name	= "rtsx_usb_ms",
+#ifdef CONFIG_PM
 		.pm	= &rtsx_usb_ms_pm_ops,
+#endif
 	},
 };
 module_platform_driver(rtsx_usb_ms_driver);
-- 
2.17.1

[4/5] memstick: rtsx_usb_ms: Support runtime power management

[Kai-Heng Feng]

In order to let host's parent device, rtsx_usb, to use USB remote wake
up signaling to do card detection, it needs to be suspended. Hence it's
necessary to add runtime PM support for the memstick host.

To keep memstick host stays suspended when it's not in use, convert the
card detection function from kthread to delayed_work, which can be
scheduled when the host is resumed and can be canceled when the host is
suspended.

Use an idle function check if there's no card and the power mode is
MEMSTICK_POWER_OFF. If both criteria are met, put the device to suspend.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 139 +++++++++++++++-------------
 1 file changed, 76 insertions(+), 63 deletions(-)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index d56f0863653f..622497554a5a 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -40,15 +40,14 @@ struct rtsx_usb_ms {
 
 	struct mutex		host_mutex;
 	struct work_struct	handle_req;
-
-	struct task_struct	*detect_ms;
-	struct completion	detect_ms_exit;
+	struct delayed_work	poll_card;
 
 	u8			ssc_depth;
 	unsigned int		clock;
 	int			power_mode;
 	unsigned char           ifmode;
 	bool			eject;
+	bool			suspend;
 };
 
 static inline struct device *ms_dev(struct rtsx_usb_ms *host)
@@ -524,7 +523,7 @@ static void rtsx_usb_ms_handle_req(struct work_struct *work)
 	int rc;
 
 	if (!host->req) {
-		pm_runtime_get_sync(ms_dev(host));
+		pm_runtime_get_noresume(ms_dev(host));
 		do {
 			rc = memstick_next_req(msh, &host->req);
 			dev_dbg(ms_dev(host), "next req %d\n", rc);
@@ -545,7 +544,7 @@ static void rtsx_usb_ms_handle_req(struct work_struct *work)
 						host->req->error);
 			}
 		} while (!rc);
-		pm_runtime_put(ms_dev(host));
+		pm_runtime_put_noidle(ms_dev(host));
 	}
 
 }
@@ -572,7 +571,7 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	dev_dbg(ms_dev(host), "%s: param = %d, value = %d\n",
 			__func__, param, value);
 
-	pm_runtime_get_sync(ms_dev(host));
+	pm_runtime_get_noresume(ms_dev(host));
 	mutex_lock(&ucr->dev_mutex);
 
 	err = rtsx_usb_card_exclusive_check(ucr, RTSX_USB_MS_CARD);
@@ -585,14 +584,14 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 			break;
 
 		if (value == MEMSTICK_POWER_ON) {
-			pm_runtime_get_sync(ms_dev(host));
+			pm_runtime_get_noresume(ms_dev(host));
 			err = ms_power_on(host);
+			if (err)
+				pm_runtime_put_noidle(ms_dev(host));
 		} else if (value == MEMSTICK_POWER_OFF) {
 			err = ms_power_off(host);
-			if (host->msh->card)
+			if (!err)
 				pm_runtime_put_noidle(ms_dev(host));
-			else
-				pm_runtime_put(ms_dev(host));
 		} else
 			err = -EINVAL;
 		if (!err)
@@ -638,7 +637,7 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	}
 out:
 	mutex_unlock(&ucr->dev_mutex);
-	pm_runtime_put(ms_dev(host));
+	pm_runtime_put_noidle(ms_dev(host));
 
 	/* power-on delay */
 	if (param == MEMSTICK_POWER && value == MEMSTICK_POWER_ON)
@@ -648,19 +647,21 @@ static int rtsx_usb_ms_set_param(struct memstick_host *msh,
 	return err;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int rtsx_usb_ms_suspend(struct device *dev)
+#ifdef CONFIG_PM
+static int rtsx_usb_ms_runtime_suspend(struct device *dev)
 {
 	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
 	struct memstick_host *msh = host->msh;
 
 	dev_dbg(ms_dev(host), "--> %s\n", __func__);
 
+	host->suspend = 1;
 	memstick_suspend_host(msh);
+
 	return 0;
 }
 
-static int rtsx_usb_ms_resume(struct device *dev)
+static int rtsx_usb_ms_runtime_resume(struct device *dev)
 {
 	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
 	struct memstick_host *msh = host->msh;
@@ -668,55 +669,72 @@ static int rtsx_usb_ms_resume(struct device *dev)
 	dev_dbg(ms_dev(host), "--> %s\n", __func__);
 
 	memstick_resume_host(msh);
+	host->suspend = 0;
+	schedule_delayed_work(&host->poll_card, 100);
+
 	return 0;
 }
-#endif /* CONFIG_PM_SLEEP */
 
-/*
- * Thread function of ms card slot detection. The thread starts right after
- * successful host addition. It stops while the driver removal function sets
- * host->eject true.
- */
-static int rtsx_usb_detect_ms_card(void *__host)
+static int rtsx_usb_ms_runtime_idle(struct device *dev)
+{
+	struct rtsx_usb_ms *host = dev_get_drvdata(dev);
+
+	dev_dbg(ms_dev(host), "--> %s\n", __func__);
+
+	if (!host->msh->card && host->power_mode == MEMSTICK_POWER_OFF) {
+		pm_schedule_suspend(dev, 0);
+		return 0;
+	}
+
+	return -EAGAIN;
+}
+
+static const UNIVERSAL_DEV_PM_OPS(rtsx_usb_ms_pm_ops,
+		rtsx_usb_ms_runtime_suspend, rtsx_usb_ms_runtime_resume,
+		rtsx_usb_ms_runtime_idle);
+#endif /* CONFIG_PM */
+
+static void rtsx_usb_ms_poll_card(struct work_struct *work)
 {
-	struct rtsx_usb_ms *host = (struct rtsx_usb_ms *)__host;
+	struct rtsx_usb_ms *host = container_of(work, struct rtsx_usb_ms,
+			poll_card.work);
 	struct rtsx_ucr *ucr = host->ucr;
-	u8 val = 0;
 	int err;
+	u8 val;
 
-	for (;;) {
-		pm_runtime_get_sync(ms_dev(host));
-		mutex_lock(&ucr->dev_mutex);
+	dev_dbg(ms_dev(host), "--> %s\n", __func__);
 
-		/* Check pending MS card changes */
-		err = rtsx_usb_read_register(ucr, CARD_INT_PEND, &val);
-		if (err) {
-			mutex_unlock(&ucr->dev_mutex);
-			goto poll_again;
-		}
+	if (host->eject || host->suspend)
+		return;
 
-		/* Clear the pending */
-		rtsx_usb_write_register(ucr, CARD_INT_PEND,
-				XD_INT | MS_INT | SD_INT,
-				XD_INT | MS_INT | SD_INT);
+	pm_runtime_get_noresume(ms_dev(host));
+	mutex_lock(&ucr->dev_mutex);
 
+	/* Check pending MS card changes */
+	err = rtsx_usb_read_register(ucr, CARD_INT_PEND, &val);
+	if (err) {
 		mutex_unlock(&ucr->dev_mutex);
+		goto poll_again;
+	}
 
-		if (val & MS_INT) {
-			dev_dbg(ms_dev(host), "MS slot change detected\n");
-			memstick_detect_change(host->msh);
-		}
+	/* Clear the pending */
+	rtsx_usb_write_register(ucr, CARD_INT_PEND,
+			XD_INT | MS_INT | SD_INT,
+			XD_INT | MS_INT | SD_INT);
 
-poll_again:
-		pm_runtime_put(ms_dev(host));
-		if (host->eject)
-			break;
+	mutex_unlock(&ucr->dev_mutex);
+	pm_runtime_put_noidle(ms_dev(host));
 
-		schedule_timeout_idle(HZ);
+	if (val & MS_INT) {
+		dev_dbg(ms_dev(host), "MS slot change detected\n");
+		memstick_detect_change(host->msh);
 	}
 
-	complete(&host->detect_ms_exit);
-	return 0;
+	pm_runtime_idle(ms_dev(host));
+
+poll_again:
+	if (!host->eject && !host->suspend)
+		schedule_delayed_work(&host->poll_card, 100);
 }
 
 static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
@@ -742,31 +760,27 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
 	host->msh = msh;
 	host->pdev = pdev;
 	host->power_mode = MEMSTICK_POWER_OFF;
+	host->eject = 0;
 	platform_set_drvdata(pdev, host);
 
 	mutex_init(&host->host_mutex);
 	INIT_WORK(&host->handle_req, rtsx_usb_ms_handle_req);
 
-	init_completion(&host->detect_ms_exit);
-	host->detect_ms = kthread_create(rtsx_usb_detect_ms_card, host,
-			"rtsx_usb_ms_%d", pdev->id);
-	if (IS_ERR(host->detect_ms)) {
-		dev_dbg(&(pdev->dev),
-				"Unable to create polling thread.\n");
-		err = PTR_ERR(host->detect_ms);
-		goto err_out;
-	}
+	INIT_DELAYED_WORK(&host->poll_card, rtsx_usb_ms_poll_card);
 
 	msh->request = rtsx_usb_ms_request;
 	msh->set_param = rtsx_usb_ms_set_param;
 	msh->caps = MEMSTICK_CAP_PAR4;
 
-	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_active(ms_dev(host));
+	pm_runtime_enable(ms_dev(host));
+
 	err = memstick_add_host(msh);
 	if (err)
 		goto err_out;
 
-	wake_up_process(host->detect_ms);
+	schedule_delayed_work(&host->poll_card, 100);
+
 	return 0;
 err_out:
 	memstick_free_host(msh);
@@ -780,8 +794,9 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	int err;
 
 	msh = host->msh;
-	host->eject = true;
+	host->eject = 1;
 	cancel_work_sync(&host->handle_req);
+	cancel_delayed_work_sync(&host->poll_card);
 
 	mutex_lock(&host->host_mutex);
 	if (host->req) {
@@ -797,7 +812,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	}
 	mutex_unlock(&host->host_mutex);
 
-	wait_for_completion(&host->detect_ms_exit);
 	memstick_remove_host(msh);
 	memstick_free_host(msh);
 
@@ -816,9 +830,6 @@ static int rtsx_usb_ms_drv_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(rtsx_usb_ms_pm_ops,
-		rtsx_usb_ms_suspend, rtsx_usb_ms_resume);
-
 static struct platform_device_id rtsx_usb_ms_ids[] = {
 	{
 		.name = "rtsx_usb_ms",
@@ -834,7 +845,9 @@ static struct platform_driver rtsx_usb_ms_driver = {
 	.id_table       = rtsx_usb_ms_ids,
 	.driver		= {
 		.name	= "rtsx_usb_ms",
+#ifdef CONFIG_PM
 		.pm	= &rtsx_usb_ms_pm_ops,
+#endif
 	},
 };
 module_platform_driver(rtsx_usb_ms_driver);

[PATCH 5/5] misc: rtsx_usb: / memstick: rtsx_usb_ms: Avoid long delay before system suspend

[Kai-Heng Feng]

There's a long power-on delay at the end of rtsx_usb_ms_set_param().
This delay is noticeable right before system suspend.

To prevent already suspended memstick host from getting powered on by PM
core, use DPM_FLAG_SMART_SUSPEND to avoid the situation.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 4 ++++
 drivers/misc/cardreader/rtsx_usb.c  | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index 622497554a5a..85eaf688962f 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -772,6 +772,10 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
 	msh->set_param = rtsx_usb_ms_set_param;
 	msh->caps = MEMSTICK_CAP_PAR4;
 
+	/* DPM_FLAG_LEAVE_SUSPENDED is not needed, the parent device will wake
+	 * up memstick host.
+	 */
+	dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_SMART_SUSPEND);
 	pm_runtime_set_active(ms_dev(host));
 	pm_runtime_enable(ms_dev(host));
 
diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
index fed83453e5c5..3c1942f9653f 100644
--- a/drivers/misc/cardreader/rtsx_usb.c
+++ b/drivers/misc/cardreader/rtsx_usb.c
@@ -671,6 +671,7 @@ static int rtsx_usb_probe(struct usb_interface *intf,
 		goto out_init_fail;
 
 #ifdef CONFIG_PM
+	dev_pm_set_driver_flags(&intf->dev, DPM_FLAG_SMART_SUSPEND | DPM_FLAG_LEAVE_SUSPENDED);
 	intf->needs_remote_wakeup = 1;
 	usb_enable_autosuspend(usb_dev);
 #endif
-- 
2.17.1

[5/5] misc: rtsx_usb: / memstick: rtsx_usb_ms: Avoid long delay before system suspend

[Kai-Heng Feng]

There's a long power-on delay at the end of rtsx_usb_ms_set_param().
This delay is noticeable right before system suspend.

To prevent already suspended memstick host from getting powered on by PM
core, use DPM_FLAG_SMART_SUSPEND to avoid the situation.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/memstick/host/rtsx_usb_ms.c | 4 ++++
 drivers/misc/cardreader/rtsx_usb.c  | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c
index 622497554a5a..85eaf688962f 100644
--- a/drivers/memstick/host/rtsx_usb_ms.c
+++ b/drivers/memstick/host/rtsx_usb_ms.c
@@ -772,6 +772,10 @@ static int rtsx_usb_ms_drv_probe(struct platform_device *pdev)
 	msh->set_param = rtsx_usb_ms_set_param;
 	msh->caps = MEMSTICK_CAP_PAR4;
 
+	/* DPM_FLAG_LEAVE_SUSPENDED is not needed, the parent device will wake
+	 * up memstick host.
+	 */
+	dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_SMART_SUSPEND);
 	pm_runtime_set_active(ms_dev(host));
 	pm_runtime_enable(ms_dev(host));
 
diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
index fed83453e5c5..3c1942f9653f 100644
--- a/drivers/misc/cardreader/rtsx_usb.c
+++ b/drivers/misc/cardreader/rtsx_usb.c
@@ -671,6 +671,7 @@ static int rtsx_usb_probe(struct usb_interface *intf,
 		goto out_init_fail;
 
 #ifdef CONFIG_PM
+	dev_pm_set_driver_flags(&intf->dev, DPM_FLAG_SMART_SUSPEND | DPM_FLAG_LEAVE_SUSPENDED);
 	intf->needs_remote_wakeup = 1;
 	usb_enable_autosuspend(usb_dev);
 #endif

Re: [PATCH 1/5] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection

[Alan Stern]

On Mon, 23 Jul 2018, Kai-Heng Feng wrote:

> Although rtsx_usb doesn't support card removal detection, card insertion
> will resume rtsx_usb by USB remote wakeup signaling.
> 
> When rtsx_usb gets resumed, also resumes its child devices,
> rtsx_usb_sdmmc and rtsx_usb_ms, to notify them there's a card in its
> slot.
> 
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
>  drivers/misc/cardreader/rtsx_usb.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
> index b97903ff1a72..fed83453e5c5 100644
> --- a/drivers/misc/cardreader/rtsx_usb.c
> +++ b/drivers/misc/cardreader/rtsx_usb.c
> @@ -723,8 +723,20 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
>  	return 0;
>  }
>  
> +static int rtsx_usb_resume_child(struct device *dev, void *data)
> +{
> +	/* No need to wake up self again */
> +	if (dev == data)
> +		return 0;

Is this test actually needed?  device_for_each_child() won't enumerate 
the device it is called for, only that device's children.

> +
> +	dev_dbg(dev, "%s called\n", __func__);

Not necessary.  People can use ftrace if they want this information.

Alan Stern

> +	pm_request_resume(dev);
> +	return 0;
> +}
> +
>  static int rtsx_usb_resume(struct usb_interface *intf)
>  {
> +	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
>  	return 0;
>  }
>  
> @@ -734,6 +746,7 @@ static int rtsx_usb_reset_resume(struct usb_interface *intf)
>  		(struct rtsx_ucr *)usb_get_intfdata(intf);
>  
>  	rtsx_usb_reset_chip(ucr);
> +	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
>  	return 0;
>  }
>  
> 

[1/5] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection

[Alan Stern]

On Mon, 23 Jul 2018, Kai-Heng Feng wrote:

> Although rtsx_usb doesn't support card removal detection, card insertion
> will resume rtsx_usb by USB remote wakeup signaling.
> 
> When rtsx_usb gets resumed, also resumes its child devices,
> rtsx_usb_sdmmc and rtsx_usb_ms, to notify them there's a card in its
> slot.
> 
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
>  drivers/misc/cardreader/rtsx_usb.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
> index b97903ff1a72..fed83453e5c5 100644
> --- a/drivers/misc/cardreader/rtsx_usb.c
> +++ b/drivers/misc/cardreader/rtsx_usb.c
> @@ -723,8 +723,20 @@ static int rtsx_usb_suspend(struct usb_interface *intf, pm_message_t message)
>  	return 0;
>  }
>  
> +static int rtsx_usb_resume_child(struct device *dev, void *data)
> +{
> +	/* No need to wake up self again */
> +	if (dev == data)
> +		return 0;

Is this test actually needed?  device_for_each_child() won't enumerate 
the device it is called for, only that device's children.

> +
> +	dev_dbg(dev, "%s called\n", __func__);

Not necessary.  People can use ftrace if they want this information.

Alan Stern

> +	pm_request_resume(dev);
> +	return 0;
> +}
> +
>  static int rtsx_usb_resume(struct usb_interface *intf)
>  {
> +	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
>  	return 0;
>  }
>  
> @@ -734,6 +746,7 @@ static int rtsx_usb_reset_resume(struct usb_interface *intf)
>  		(struct rtsx_ucr *)usb_get_intfdata(intf);
>  
>  	rtsx_usb_reset_chip(ucr);
> +	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
>  	return 0;
>  }
>  
>
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Re: [PATCH 1/5] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection

[Kai Heng Feng]

> On Jul 23, 2018, at 10:19 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
>
> On Mon, 23 Jul 2018, Kai-Heng Feng wrote:
>
>> Although rtsx_usb doesn't support card removal detection, card insertion
>> will resume rtsx_usb by USB remote wakeup signaling.
>>
>> When rtsx_usb gets resumed, also resumes its child devices,
>> rtsx_usb_sdmmc and rtsx_usb_ms, to notify them there's a card in its
>> slot.
>>
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>> ---
>>  drivers/misc/cardreader/rtsx_usb.c | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/misc/cardreader/rtsx_usb.c  
>> b/drivers/misc/cardreader/rtsx_usb.c
>> index b97903ff1a72..fed83453e5c5 100644
>> --- a/drivers/misc/cardreader/rtsx_usb.c
>> +++ b/drivers/misc/cardreader/rtsx_usb.c
>> @@ -723,8 +723,20 @@ static int rtsx_usb_suspend(struct usb_interface  
>> *intf, pm_message_t message)
>>  	return 0;
>>  }
>>
>> +static int rtsx_usb_resume_child(struct device *dev, void *data)
>> +{
>> +	/* No need to wake up self again */
>> +	if (dev == data)
>> +		return 0;
>
> Is this test actually needed?  device_for_each_child() won't enumerate
> the device it is called for, only that device's children.

Ok, I'll update this part.

>
>> +
>> +	dev_dbg(dev, "%s called\n", __func__);
>
> Not necessary.  People can use ftrace if they want this information.

Sure I'll remove it.
This is to make the change more aligned with the original code. It uses  
similar function on other places too.

Kai-Heng

>
> Alan Stern
>
>> +	pm_request_resume(dev);
>> +	return 0;
>> +}
>> +
>>  static int rtsx_usb_resume(struct usb_interface *intf)
>>  {
>> +	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
>>  	return 0;
>>  }
>>
>> @@ -734,6 +746,7 @@ static int rtsx_usb_reset_resume(struct  
>> usb_interface *intf)
>>  		(struct rtsx_ucr *)usb_get_intfdata(intf);
>>
>>  	rtsx_usb_reset_chip(ucr);
>> +	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
>>  	return 0;
>>  }

[1/5] misc: rtsx_usb: Use USB remote wakeup signaling for card insertion detection

[Kai-Heng Feng]

> On Jul 23, 2018, at 10:19 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
>
> On Mon, 23 Jul 2018, Kai-Heng Feng wrote:
>
>> Although rtsx_usb doesn't support card removal detection, card insertion
>> will resume rtsx_usb by USB remote wakeup signaling.
>>
>> When rtsx_usb gets resumed, also resumes its child devices,
>> rtsx_usb_sdmmc and rtsx_usb_ms, to notify them there's a card in its
>> slot.
>>
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
>> ---
>>  drivers/misc/cardreader/rtsx_usb.c | 13 +++++++++++++
>>  1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/misc/cardreader/rtsx_usb.c  
>> b/drivers/misc/cardreader/rtsx_usb.c
>> index b97903ff1a72..fed83453e5c5 100644
>> --- a/drivers/misc/cardreader/rtsx_usb.c
>> +++ b/drivers/misc/cardreader/rtsx_usb.c
>> @@ -723,8 +723,20 @@ static int rtsx_usb_suspend(struct usb_interface  
>> *intf, pm_message_t message)
>>  	return 0;
>>  }
>>
>> +static int rtsx_usb_resume_child(struct device *dev, void *data)
>> +{
>> +	/* No need to wake up self again */
>> +	if (dev == data)
>> +		return 0;
>
> Is this test actually needed?  device_for_each_child() won't enumerate
> the device it is called for, only that device's children.

Ok, I'll update this part.

>
>> +
>> +	dev_dbg(dev, "%s called\n", __func__);
>
> Not necessary.  People can use ftrace if they want this information.

Sure I'll remove it.
This is to make the change more aligned with the original code. It uses  
similar function on other places too.

Kai-Heng

>
> Alan Stern
>
>> +	pm_request_resume(dev);
>> +	return 0;
>> +}
>> +
>>  static int rtsx_usb_resume(struct usb_interface *intf)
>>  {
>> +	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
>>  	return 0;
>>  }
>>
>> @@ -734,6 +746,7 @@ static int rtsx_usb_reset_resume(struct  
>> usb_interface *intf)
>>  		(struct rtsx_ucr *)usb_get_intfdata(intf);
>>
>>  	rtsx_usb_reset_chip(ucr);
>> +	device_for_each_child(&intf->dev, &intf->dev, rtsx_usb_resume_child);
>>  	return 0;
>>  }
---
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[PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection

[Kai-Heng Feng]

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 <kai.heng.feng@canonical.com>
---
 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..5f16a8826401 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(host->dev.parent);
 	dev_dbg(&host->dev, "memstick_check finished\n");
 }
 
-- 
2.17.1

Re: [PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection

[Kai-Heng Feng]

> On 2018Jul26, at 01:56, Alan Stern <stern@rowland.harvard.edu> wrote:
> 
> On Wed, 25 Jul 2018, Kai-Heng Feng wrote:
> 
>> 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 <kai.heng.feng@canonical.com>
>> ---
>> 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");
>> }
> 
> This should be pm_runtime_put(), not _put_noidle().  The reason is
> because if this call causes the PM runtime usage count to drop to 0,
> you do want the device to go into runtime suspend.

Will update in next version, thanks!

Kai-Heng

> 
> Alan Stern

Re: [PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection

[Alan Stern]

On Wed, 25 Jul 2018, Kai-Heng Feng wrote:

> 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 <kai.heng.feng@canonical.com>
> ---
>  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");
>  }

This should be pm_runtime_put(), not _put_noidle().  The reason is
because if this call causes the PM runtime usage count to drop to 0,
you do want the device to go into runtime suspend.

Alan Stern

[PATCH 2/5] memstick: Prevent memstick host from getting runtime suspended during card detection

[Kai-Heng Feng]

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 <kai.heng.feng@canonical.com>
---
 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");
 }
 
-- 
2.17.1