From: Christoph Hellwig <hch@infradead.org>
To: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>,
aacraid@microsemi.com, linux-scsi@vger.kernel.org,
RaghavaAditya.Renukunta@microsemi.com,
david.carroll@microsemi.com, brking@linux.vnet.ibm.com,
dougmill@linux.vnet.ibm.com, stable@vger.kernel.org
Subject: Re: [PATCH] scsi: aacraid: Add a small delay after IOP reset
Date: Tue, 19 Sep 2017 08:52:22 -0700 [thread overview]
Message-ID: <20170919155222.GA24688@infradead.org> (raw)
In-Reply-To: <6958d5da-8f9a-ff6b-ccea-16c335b24530@linux.vnet.ibm.com>
On Tue, Sep 19, 2017 at 12:49:21PM -0300, Guilherme G. Piccoli wrote:
> On 09/19/2017 12:37 PM, Christoph Hellwig wrote:
> > On Tue, Sep 19, 2017 at 12:11:55PM -0300, Guilherme G. Piccoli wrote:
> >> src_writel(dev, MUnit.IDR, IOP_SRC_RESET_MASK);
> >> +
> >> + msleep(5000);
> >
> > src_writel is a writel, and thus a posted MMIO write. You'll need
> > to have to a read first to make it a reliable timing base.
> >
>
> Just for my full understanding - you're saying a readl BEFORE
> src_writel() or AFTER src_writel() ?
AFTER.
> I could add a read to some dummy register, but notice it was a sequence
> of readl's on aac_is_ctrl_up_and_running() that caused the failure of
> reset...
Oh, ouch. I guess in that case we'll need to do the writel and pray,
but that would need a big comment explaining what's going on there.
next prev parent reply other threads:[~2017-09-19 15:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-19 15:11 [PATCH] scsi: aacraid: Add a small delay after IOP reset Guilherme G. Piccoli
2017-09-19 15:37 ` Christoph Hellwig
2017-09-19 15:49 ` Guilherme G. Piccoli
2017-09-19 15:52 ` Christoph Hellwig [this message]
2017-09-19 15:58 ` Guilherme G. Piccoli
2017-09-19 17:05 ` James Bottomley
2017-09-19 19:15 ` Guilherme G. Piccoli
2017-09-21 16:19 ` Dave Carroll
2017-09-25 21:09 ` Guilherme G. Piccoli
2017-09-25 21:34 ` Martin K. Petersen
2017-09-27 19:26 ` Dave Carroll
2017-09-28 1:42 ` Martin K. Petersen
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