From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Phillip Susi <phill@thesusis.net>, Christoph Hellwig <hch@infradead.org>
Cc: linux-ide@vger.kernel.org
Subject: Re: Drive reset as an EH strategy when write cache is enabled
Date: Wed, 02 Dec 2020 10:58:39 -0800 [thread overview]
Message-ID: <9a72bd02bd9230cc2258065faf01eb846530fd7d.camel@HansenPartnership.com> (raw)
In-Reply-To: <87blfc19u5.fsf@vps.thesusis.net>
On Wed, 2020-12-02 at 10:55 -0500, Phillip Susi wrote:
> Christoph Hellwig writes:
>
> > If the device drops the content of the volatile write on a reset
> > we'll have much problems than that..
>
> How could it not? The write cache is empty after a power on reset
> and certainly a "hard" reset should be the same as a power on reset.
As Christoph said it would be stupid behaviour to invalidate the cache
after a hard reset because it would cause all deferred writes to fail.
The SCSI standards committee did initially assume manufacturers knew
this, but it was codified in SBC-4 and beyond with an explicit list of
conditions under which the write back cache could be lost, which
doesn't include hard reset.
James
next prev parent reply other threads:[~2020-12-02 18:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 17:24 Drive reset as an EH strategy when write cache is enabled Phillip Susi
2020-12-02 15:03 ` Christoph Hellwig
2020-12-02 15:55 ` Phillip Susi
2020-12-02 18:58 ` James Bottomley [this message]
2020-12-02 22:11 ` Phillip Susi
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