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Message-ID: <20170115231049.GC14446@mtj.duckdns.org>
Date: Sun, 15 Jan 2017 18:10:49 -0500
From: Tejun Heo <tj@...nel.org>
To: Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc: Kevin Hilman <khilman@...nel.org>, Sekhar Nori <nsekhar@...com>,
Patrick Titiano <ptitiano@...libre.com>,
Michael Turquette <mturquette@...libre.com>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Russell King <linux@...linux.org.uk>,
David Lechner <david@...hnology.com>,
linux-ide@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 04/10] sata: hardreset: retry if phys link is down
Hello,
On Fri, Jan 13, 2017 at 01:37:58PM +0100, Bartosz Golaszewski wrote:
> The sata core driver already retries to resume the link because some
> controllers ignore writes to the SControl register.
>
> We have a use case with the da850 SATA controller where at PLL0
> frequency of 456MHz (needed to properly service the LCD controller)
> the chip becomes unstable and the hardreset operation is ignored the
> first time 50% of times.
>
> Retrying just the resume operation doesn't work - we need to issue
> the phy/wake reset again to make it work.
>
> If ata_phys_link_offline() returns true in sata_link_hardreset(),
> retry a couple times before really giving up.
I think it'd be better to implement the driver specific implementation
rather than changing the behavior for everybody.
Thanks.
--
tejun
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