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Date: Sun, 15 Jan 2017 18:10:49 -0500
From: Tejun Heo <tj@kernel.org>
To: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Kevin Hilman <khilman@kernel.org>, Sekhar Nori <nsekhar@ti.com>,
        Patrick Titiano <ptitiano@baylibre.com>,
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        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 04/10] sata: hardreset: retry if phys link is down
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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