From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: Re: REQ_PM vs REQ_TYPE_PM_RESUME Date: Wed, 08 Jan 2014 16:50:46 -0500 Message-ID: <52CDC836.4000201@ubuntu.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-ide-owner@vger.kernel.org To: Alan Stern Cc: Aaron Lu , Sujit Reddy Thumma , todd.e.brandt@linux.intel.com, tj@kernel.org, JBottomley@parallels.com, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, Linux-pm mailing list , "Rafael J. Wysocki" List-Id: linux-pm@vger.kernel.org -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 1/8/2014 4:21 PM, Alan Stern wrote: > I never saw your patches. Where were they posted? Higher up in this thread on linux-ide and linux-scsi. Subject was Let sleeping disks lie. > If you issue the REQUEST SENSE command in the usual way (going > through the SCSI and block layers), and the disk is already in > runtime suspend, it won't do what you want. The block layer won't > deliver requests until the device leaves the RPM_SUSPENDED state. > In addition, when it receives the command the block layer will > submit a deferred runtime-resume request, which rather defeats the > whole purpose. Right, which is why I left the device in the active state and used the pre/post_suspend functions to change the queue into the RPM_SUSPENDING state, then either complete the transition to RPM_SUSPENDED, or bail out and go back to RPM_ACTIVE. > What happens with non-ATA disks? Same thing: they return a sense status that either says they are suspended, stopped, or normal. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJSzcg2AAoJEI5FoCIzSKrw7wcIAJLiliMYnoHLm/dGWHhhfcnb ELJLLAhhWsOIQmHiV1svdy0F7EuKi3KF9qJ9JwCaAspO0w8q24UGhvQW20uSH9Md JliKhn6eBY/NFTctaVP2tnOcc4vevCndJfEScBlWxI82MWMC1TV3lA7xPtcJ5ocX LMBLPXpr0qypisgmu/tAnwTPQVyU4WUkgMmG9us4w3BgCkvI/oXf4oDKFkCNgUye FX16NTZPR6iaIK+YJMG3uKCSD4CQjTnKJNXGR89XKJG+Z9v04jyQgWs7kgvqCov9 F5j+yueyMVlveGPHmNwhElHEPT2UWSoyQbonuOrYQZ+Db+xJBOxzoY8Jgq9lWVI= =+vwf -----END PGP SIGNATURE-----