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Date:   Wed, 04 Jan 2023 10:33:56 +0100
From:   "Sven Peter" <sven@svenpeter.dev>
To:     "Hector Martin" <marcan@marcan.st>,
        "Keith Busch" <kbusch@kernel.org>, "axboe@fb.com" <axboe@fb.com>,
        "hch@lst.de" <hch@lst.de>, "sagi@grimberg.me" <sagi@grimberg.me>
Cc:     "Uday Shankar" <ushankar@purestorage.com>,
        "Alyssa Rosenzweig" <alyssa@rosenzweig.io>, asahi@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nvme-apple: Add NVME_QUIRK_IDENTIFY_CNS quirk to fix regression
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Hi,


On Wed, Jan 4, 2023, at 10:21, Hector Martin wrote:
> From the get-go, this driver and the ANS syslog have been complaining
> about namespace identification. In 6.2-rc1, commit 811f4de0344d ("nvme:
> avoid fallback to sequential scan due to transient issues") regressed
> the driver by no longer allowing fallback to sequential namespace scans,
> leaving us with no namespaces.
>
> It turns out that the real problem is that this controller claiming
> NVMe 1.1 compat is treating the CNS field as a binary field, as in NVMe
> 1.0. This already has a quirk, NVME_QUIRK_IDENTIFY_CNS, so set it for
> the controller to fix all this nonsense (including other errors
> triggered by other CNS commands).
>
> Fixes: 811f4de0344d ("nvme: avoid fallback to sequential scan due to 
> transient issues")
> Fixes: 5bd2927aceba ("nvme-apple: Add initial Apple SoC NVMe driver")
> Signed-off-by: Hector Martin <marcan@marcan.st>

Nice, I've been meaning to look into those weird namespace scanning errors
for a while now but never got around to it because they didn't break anything.

There's a chance this is also required for the later T2/x86 Macs in pci.c
(PCI_DEVICE(PCI_VENDOR_ID_APPLE, 0x2005)) since they share a similar firmware but
I don't have access to those to test if this is actually required.

Reviewed-by: Sven Peter <sven@svenpeter.dev>


Best,

Sven