This add a very conservative but simple implementation for runtime PM to the sd scsi driver: Resume when opened (mounted) and suspend when released (unmounted).
Improvements that allow suspending while a device is "open" can be added later, but now we save power when no filesystem is mounted and runtime PM is enabled. Signed-off-by: Martin Kepplinger <[email protected]> --- drivers/scsi/sd.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index d90fefffe31b..fe4cb7c50ec1 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -1372,6 +1372,7 @@ static int sd_open(struct block_device *bdev, fmode_t mode) SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_open\n")); sdev = sdkp->device; + scsi_autopm_get_device(sdev); /* * If the device is in error recovery, wait until it is done. @@ -1418,6 +1419,9 @@ static int sd_open(struct block_device *bdev, fmode_t mode) error_out: scsi_disk_put(sdkp); + + scsi_autopm_put_device(sdev); + return retval; } @@ -1441,6 +1445,8 @@ static void sd_release(struct gendisk *disk, fmode_t mode) SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_release\n")); + scsi_autopm_put_device(sdev); + if (atomic_dec_return(&sdkp->openers) == 0 && sdev->removable) { if (scsi_block_when_processing_errors(sdev)) scsi_set_medium_removal(sdev, SCSI_REMOVAL_ALLOW); -- 2.20.1
