From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 17 Jul 2018 23:38:53 +0800 From: Ming Lei To: Bart Van Assche Cc: "hch@lst.de" , "jthumshirn@suse.de" , "linux-block@vger.kernel.org" , "linux-pm@vger.kernel.org" , "martin.petersen@oracle.com" , "hare@suse.de" , "axboe@kernel.dk" , "linux-scsi@vger.kernel.org" , "rjw@rjwysocki.net" , "stern@rowland.harvard.edu" , "gregkh@linuxfoundation.org" , "jejb@linux.vnet.ibm.com" , "adrian.hunter@intel.com" Subject: Re: [PATCH RFC V2 3/3] scsi_mq: enable runtime PM Message-ID: <20180717153847.GB8973@ming.t460p> References: <20180713080602.31602-1-ming.lei@redhat.com> <20180713080602.31602-4-ming.lei@redhat.com> <20180717132411.GI13582@lst.de> <20180717153031.GA8973@ming.t460p> <07874eaab2d93728afe3f220cd0efa8f41d4955a.camel@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <07874eaab2d93728afe3f220cd0efa8f41d4955a.camel@wdc.com> List-ID: 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