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From:   Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Date:   Thu, 5 May 2022 13:02:12 +0500
Message-ID: <CABXGCsNaV_BZ7sm8MOXEOGGJGNS=TX7=7azZTM3Ky5z15bMN3Q@mail.gmail.com>
Subject: Re: [BUG][5.18rc5] nvme nvme0: controller is down; will reset:
 CSTS=0xffffffff, PCI_STATUS=0x10
To:     Keith Busch <kbusch@kernel.org>
Cc:     linux@leemhuis.info,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        linux-nvme@lists.infradead.org, luto@kernel.org
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On Thu, May 5, 2022 at 10:19 AM Keith Busch <kbusch@kernel.org> wrote:
> I think you did misinterpret the results. The max latency just says which power
> state is the deepest it will request APST, and your controller's reported
> values will allow the deepest low power state your controller supports, which
> is known to cause problems with some platform/controller combinations.
>
> The troubleshooting steps for your observation is to:
>
>   1. Turn off APST (nvme_core.default_ps_max_latency_us=0)
>   2. Turn off APSM (pcie_aspm=off)
>   3. Turn off both
>
> Typically one of those resolves the issue.

Thanks.
To make it easier for everyone to diagnose such problems, it would be
great if every switching between power save modes would be written to
the kernel log (when console_loglevel is KERN_DEBUG)
If APST is culprit, we would have seen the change in the power state
in the kernel logs before the message "nvme nvme0: controller is
down;".

-- 
Best Regards,
Mike Gavrilov.