Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210520033315.490584-1-koba.ko@canonical.com>
 <20210525074426.GA14916@lst.de> <CAJB-X+UFi-iAkRBZQUsd6B_P+Bi-TAa_sQjnhJagD0S91WoFUQ@mail.gmail.com>
 <20210526024934.GB3704949@dhcp-10-100-145-180.wdc.com>
In-Reply-To: <20210526024934.GB3704949@dhcp-10-100-145-180.wdc.com>
From:   Kai-Heng Feng <kai.heng.feng@canonical.com>
Date:   Wed, 26 May 2021 20:11:41 +0800
Message-ID: <CAAd53p7xabD2t__=t67uRLrrFOB7YGgr_GMhi6L48PFGhNe80w@mail.gmail.com>
Subject: Re: [PATCH] nvme-pci: Avoid to go into d3cold if device can't use npss.
To:     Keith Busch <kbusch@kernel.org>
Cc:     Koba Ko <koba.ko@canonical.com>, Christoph Hellwig <hch@lst.de>,
        Jens Axboe <axboe@fb.com>, Sagi Grimberg <sagi@grimberg.me>,
        linux-nvme <linux-nvme@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Henrik Juul Hansen <hjhansen2020@gmail.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Linux PCI <linux-pci@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Wed, May 26, 2021 at 10:49 AM Keith Busch <kbusch@kernel.org> wrote:
>
> On Wed, May 26, 2021 at 10:02:27AM +0800, Koba Ko wrote:
> > On Tue, May 25, 2021 at 3:44 PM Christoph Hellwig <hch@lst.de> wrote:
> > >
> > > On Thu, May 20, 2021 at 11:33:15AM +0800, Koba Ko wrote:
> > > > After resume, host can't change power state of the closed controller
> > > > from D3cold to D0.
> > >
> > > Why?
> > As per Kai-Heng said, it's a regression introduced by commit
> > b97120b15ebd ("nvme-pci:
> > use simple suspend when a HMB is enabled"). The affected NVMe is using HMB.
>
> That really doesn't add up. The mentioned commit restores the driver
> behavior for HMB drives that existed prior to d916b1be94b6d from kernel
> 5.3. Is that NVMe device broken in pre-5.3 kernels, too?

Quite likely. The system in question is a late 2020 Ice Lake laptop,
so it was released after 5.3 kernel.

Kai-Heng