On Tue, Jul 17, 2018 at 03:34:35PM +0000, Bart Van Assche wrote: > On Tue, 2018-07-17 at 23:30 +0800, Ming Lei wrote: > > On Tue, Jul 17, 2018 at 03:24:11PM +0200, Christoph Hellwig wrote: > > > On Fri, Jul 13, 2018 at 04:06:02PM +0800, Ming Lei wrote: > > > > Usually SCSI supports runtime PM, so pass BLK_MQ_F_SUPPORT_RPM to blk-mq > > > > core for enabling block runtime PM. > > > > > > I still think enabling this unconditionally for any SCSI device was > > > a mistake, and it is even more so for blk-mq. > > > > > > Please only opt in for ufs, ATA first, adding others if wanted by > > > maintainers. > > > > No, this way will cause regression because runtime PM works for > > all sd/sr device actually, and it isn't related with scsi host. > > For which SCSI devices other than ufs and ATA do we need PM support? As I said, it is any sd/sr device, which can be put down by runtime PM via START_STOP command if it isn't used for a while. Thanks, Ming