Some device may enter into a power state when events checking is no
longer necessary, this patch introduces the PM_QOS_FLAG_NO_POLL flag
and once set, events checking work function in block layer will skip
invoke the disk's check_events callback.
This will be used by ZPODD, when ODD is powered off, it doesn't make
sense to poll for media change events anymore.
Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx>
---
block/genhd.c | 8 +++++++-
include/linux/pm_qos.h | 1 +
2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/block/genhd.c b/block/genhd.c
index 6cace66..b0092bb 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -18,6 +18,7 @@
#include <linux/mutex.h>
#include <linux/idr.h>
#include <linux/log2.h>
+#include <linux/pm_qos.h>
#include "blk.h"
@@ -1595,9 +1596,14 @@ static void disk_events_workfn(struct work_struct *work)
unsigned int events;
unsigned long intv;
int nr_events = 0, i;
+ enum pm_qos_flags_status stat;
/* check events */
- events = disk->fops->check_events(disk, clearing);
+ stat = dev_pm_qos_flags(disk->driverfs_dev, PM_QOS_FLAG_NO_POLL);
+ if (stat == PM_QOS_FLAGS_ALL)
+ events = 0;
+ else
+ events = disk->fops->check_events(disk, clearing);
/* accumulate pending events and schedule next poll if necessary */
spin_lock_irq(&ev->lock);
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 5a95013..318a422 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -36,6 +36,7 @@ enum pm_qos_flags_status {
#define PM_QOS_FLAG_NO_POWER_OFF (1 << 0)
#define PM_QOS_FLAG_REMOTE_WAKEUP (1 << 1)
+#define PM_QOS_FLAG_NO_POLL (1 << 3)
struct pm_qos_request {
struct plist_node node;
--
1.7.12.4
--
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