From mboxrd@z Thu Jan 1 00:00:00 1970 From: rafael@kernel.org (Rafael J. Wysocki) Date: Wed, 7 Aug 2019 12:54:08 +0200 Subject: [Regression] Commit "nvme/pci: Use host managed power state for suspend" has problems In-Reply-To: <20190807104500.GB11356@lst.de> References: <4323ed84dd07474eab65699b4d007aaf@AUSX13MPC105.AMER.DELL.COM> <20190731221956.GB15795@localhost.localdomain> <2763495.NmdaWeg79L@kreacher> <20190807104500.GB11356@lst.de> Message-ID: On Wed, Aug 7, 2019@12:45 PM Christoph Hellwig wrote: > > On Wed, Aug 07, 2019@11:48:33AM +0200, Rafael J. Wysocki wrote: > > So I think I know what the problem is here. > > > > If ASPM is disabled for the NVMe device (which is the case on my machine by default), > > skipping the bus-level PM in nvme_suspend() causes the PCIe link of it to stay up and > > that prevents the SoC from getting into deeper package C-states. > > > > If I change the ASPM policy to "powersave" (through the module parameter in there), > > ASPM gets enabled for the NVMe drive and I can get into PC10 via S2Idle with plain 5.3-rc3. > > > > However, that's a bit less than straightforward, so I'm going to post a patch to make > > nvme_suspend() fall back to the "old ways" if ASPM is not enabled for the target device. > > Sounds sensibel. > > FYI your mail is not properly formatted and has way too long lines. Sorry about that.