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From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
Date:   Thu, 9 Jun 2022 10:34:11 +0200
Message-ID: <CAHmME9o-orF52HzkT80054e3Op5fLOcTHb-KHpvvU7H3FpAJ7A@mail.gmail.com>
Subject: Re: 2 second nvme initialization delay regression in 5.18 [Was: Re:
 [bug report]nvme0: Admin Cmd(0x6), I/O Error (sct 0x0 / sc 0x2) MORE DNR
 observed during blktests]
To:     monish.kumar.r@intel.com
Cc:     "open list:NVM EXPRESS DRIVER" <linux-nvme@lists.infradead.org>,
        Sagi Grimberg <sagi@grimberg.me>, alan.adamson@oracle.com,
        LKML <linux-kernel@vger.kernel.org>,
        Yi Zhang <yi.zhang@redhat.com>,
        Keith Busch <kbusch@kernel.org>, axboe@fb.com,
        Christoph Hellwig <hch@lst.de>, abhijeet.rao@intel.com
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Precedence: bulk

Hey again,

Figured it out. 2.3 seconds to be exact... It looks like this is caused by:

bc360b0b1611 ("nvme-pci: add quirks for Samsung X5 SSDs")
https://lore.kernel.org/all/20220316075449.18906-1-monish.kumar.r@intel.com/

This commit doesn't have any justification and got applied without
much discussion. Perhaps Monish could supply some more info about why
this is needed here? FTR, I have no issues on my system when reverting
that. Perhaps it should be reverted. (I can send a revert commit for
that if necessary.)

Looking further, however, the PCIe ID is said to be for a "Samsung
X5", which Google says is a portable thunderbolt drive. Is the PCIe ID
correct? On my system, this is the PCIe ID of a Samsung 970 EVO Plus.
Is it possible that Monish copied and pasted the wrong PCIe ID? Or has
Samsung *reused* the same PCIe ID on both devices? In which case, we'd
need some additional data for that quirk to avoid the delay.

Also note that this (potentially errant) commit has been backported to stable.

Jason