This patch adds runtime pm support for sr. It did this by increasing the runtime usage_count of the device when: - its block device is opened; - the events checking is to run.
And decreasing the runtime usage_count of the device when: - its block device is closed; - After the events checking is done. The idea is discussed in this mail thread: http://thread.gmane.org/gmane.linux.acpi.devel/55243/focus=52703 Signed-off-by: Aaron Lu <aaron...@intel.com> --- drivers/scsi/sr.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c index 5fc97d2..4d1a610 100644 --- a/drivers/scsi/sr.c +++ b/drivers/scsi/sr.c @@ -45,6 +45,7 @@ #include <linux/blkdev.h> #include <linux/mutex.h> #include <linux/slab.h> +#include <linux/pm_runtime.h> #include <asm/uaccess.h> #include <scsi/scsi.h> @@ -146,7 +147,8 @@ static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk) kref_get(&cd->kref); if (scsi_device_get(cd->device)) goto out_put; - goto out; + if (!scsi_autopm_get_device(cd->device)) + goto out; out_put: kref_put(&cd->kref, sr_kref_release); @@ -162,6 +164,7 @@ static void scsi_cd_put(struct scsi_cd *cd) mutex_lock(&sr_ref_mutex); kref_put(&cd->kref, sr_kref_release); + scsi_autopm_put_device(sdev); scsi_device_put(sdev); mutex_unlock(&sr_ref_mutex); } @@ -211,7 +214,7 @@ static unsigned int sr_check_events(struct cdrom_device_info *cdi, unsigned int clearing, int slot) { struct scsi_cd *cd = cdi->handle; - bool last_present; + bool last_present = cd->media_present; struct scsi_sense_hdr sshdr; unsigned int events; int ret; @@ -220,6 +223,8 @@ static unsigned int sr_check_events(struct cdrom_device_info *cdi, if (CDSL_CURRENT != slot) return 0; + scsi_autopm_get_device(cd->device); + events = sr_get_events(cd->device); cd->get_event_changed |= events & DISK_EVENT_MEDIA_CHANGE; @@ -246,10 +251,9 @@ static unsigned int sr_check_events(struct cdrom_device_info *cdi, } if (!(clearing & DISK_EVENT_MEDIA_CHANGE)) - return events; + goto out; do_tur: /* let's see whether the media is there with TUR */ - last_present = cd->media_present; ret = scsi_test_unit_ready(cd->device, SR_TIMEOUT, MAX_RETRIES, &sshdr); /* @@ -270,7 +274,7 @@ do_tur: } if (cd->ignore_get_event) - return events; + goto out; /* check whether GET_EVENT is reporting spurious MEDIA_CHANGE */ if (!cd->tur_changed) { @@ -287,6 +291,18 @@ do_tur: cd->tur_changed = false; cd->get_event_changed = false; +out: + /* + * If there is no medium detected or the medium has been there + * since last poll, try to suspend the device. Otherwise, keep + * it active for one more poll interval so that if user space + * application opens the block device, we can avoid a runtime + * status change. + */ + pm_runtime_put_noidle(&cd->device->sdev_gendev); + if (!cd->media_present || last_present) + pm_runtime_suspend(&cd->device->sdev_gendev); + return events; } @@ -718,6 +734,8 @@ static int sr_probe(struct device *dev) sdev_printk(KERN_DEBUG, sdev, "Attached scsi CD-ROM %s\n", cd->cdi.name); + scsi_autopm_put_device(cd->device); + return 0; fail_put: @@ -965,6 +983,8 @@ static int sr_remove(struct device *dev) { struct scsi_cd *cd = dev_get_drvdata(dev); + scsi_autopm_get_device(cd->device); + blk_queue_prep_rq(cd->device->request_queue, scsi_prep_fn); del_gendisk(cd->disk); -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
