Re: [PATCH] libata: sata_down_spd_limit should return if driver has not recorded sstatus speed

Tejun Heo
2017-12-04T21:57:39Z

On Tue, Nov 14, 2017 at 04:17:25PM -0600, David Milburn wrote:
> During hotplug, it is possible for 6Gbps link speed to
> be limited all the way down to 1.5 Gbps which may lead
> to a slower link speed when drive is re-connected.
>
> This behavior has been seen on a Intel Lewisburg SATA
> controller (8086:a1d2) with HGST HUH728080ALE600 drive
> where SATA link speed was limited to 1.5 Gbps and
> when re-connected the link came up 3.0 Gbps.
>
> This patch was retested on above configuration and
> showed the hotplugged link to come back online at max
> speed (6Gbps). I did not see the downgrade when testing
> on Intel C600/X79, but retested patched linux-4.14-rc5
> kernel and didn't see any side effects from this
> change. Also, successfully retested hotplug on port
> multiplier 3Gbps link.
>
> Signed-off-by: David Milburn <dmilburn@redhat.com>

Applied to libata/for-4.15-fixes.

Thanks.

--
tejun