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scsi: Allow auto suspend override by low-level driver

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Until now the scsi mid-layer forbids runtime suspend till userspace
enables it. This is mainly to quarantine some disks with broken
runtime power management or have high latencies executing suspend
resume callbacks. If the userspace doesn't enable the runtime suspend
the underlying hardware will be always on even when it is not doing
any useful work and thus wasting power.

Some low-level drivers for the controllers can efficiently use runtime
power management to reduce power consumption and improve battery life.
Allow runtime suspend parameters override within the LLD itself
instead of waiting for userspace to control the power management.

Change-Id: I03e96a89d19c174deeb5bd4f94136c77073eb009
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
[subhashj@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
This commit is contained in:
Sujit Reddy Thumma 2013-12-06 19:02:57 +05:30 • committed by David Keitel
parent d2e7a77a9a
commit c6b82e8bca
4 changed files with 13 additions and 1 deletions
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4
drivers/scsi/scsi_scan.c
View file

@ -970,6 +970,10 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
transport_configure_device(&sdev->sdev_gendev);
/* The LLD can override auto suspend tunables in ->slave_configure() */
sdev->use_rpm_auto = 0;
sdev->autosuspend_delay = SCSI_DEFAULT_AUTOSUSPEND_DELAY;
if (sdev->host->hostt->slave_configure) {
ret = sdev->host->hostt->slave_configure(sdev);
if (ret) {

3
drivers/scsi/scsi_sysfs.c
View file

@ -1044,7 +1044,8 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
device_enable_async_suspend(&sdev->sdev_gendev);
scsi_autopm_get_target(starget);
pm_runtime_set_active(&sdev->sdev_gendev);
pm_runtime_forbid(&sdev->sdev_gendev);
if (!sdev->use_rpm_auto)
pm_runtime_forbid(&sdev->sdev_gendev);
pm_runtime_enable(&sdev->sdev_gendev);
scsi_autopm_put_target(starget);

3
drivers/scsi/sd.c
View file

@ -3049,6 +3049,9 @@ static void sd_probe_async(void *data, async_cookie_t cookie)
}
blk_pm_runtime_init(sdp->request_queue, dev);
if (sdp->autosuspend_delay >= 0)
pm_runtime_set_autosuspend_delay(dev, sdp->autosuspend_delay);
add_disk(gd);
if (sdkp->capacity)
sd_dif_config_host(sdkp);

4
include/scsi/scsi_device.h
View file

@ -175,6 +175,10 @@ struct scsi_device {
unsigned no_dif:1; /* T10 PI (DIF) should be disabled */
unsigned broken_fua:1; /* Don't set FUA bit */
unsigned lun_in_cdb:1; /* Store LUN bits in CDB[1] */
unsigned use_rpm_auto:1; /* Enable runtime PM auto suspend */
#define SCSI_DEFAULT_AUTOSUSPEND_DELAY -1
int autosuspend_delay;
atomic_t disk_events_disable_depth; /* disable depth for disk events */