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Date:   Thu, 8 Apr 2021 12:30:16 +0200
From:   Javier =?utf-8?B?R29uesOhbGV6?= <javier.gonz@samsung.com>
To:     Christoph Hellwig <hch@lst.de>
CC:     Keith Busch <kbusch@kernel.org>,
        Dmitry Monakhov <dmtrmonakhov@yandex-team.ru>,
        <linux-kernel@vger.kernel.org>, <linux-nvme@lists.infradead.org>,
        <Chaitanya.Kulkarni@wdc.com>
Subject: Re: [PATCH 1/1] nvme-pci: add the DISABLE_WRITE_ZEROES quirk for a
 Samsung PM1725a
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On 23.03.2021 13:43, Javier González wrote:
>On 23.03.2021 13:31, Christoph Hellwig wrote:
>>On Tue, Mar 23, 2021 at 09:37:49AM +0100, Javier González wrote:
>>>Quick question. It seems like the current quirk simply disables
>>>write-zeroes. Would you be open for a quirk that aligns with MDTS for
>>>models that implemented it this way before TP4040?
>>
>>Aligning to MDTS is our current behavior, although all kernels up to
>>5.11 had a bug in the calculation.
>
>I see. Let me check internally and see what's going on with
>write-zeroes on this model.

We still need to confirm, but it seems like MDTS for write-zeroes is
reported wrong in the FW that Dmitry is using. We can at least reproduce
it.

Would it be a possibility to add quirk infrastructure to hardcode MDTS
for FW versions prior TP4040?

Another possibility is to add quirks to the TP4040 support patches to
enable this - it might also help reduce the list of models currently
blacklisted for write-zeroes.