Re: PMP device port link speed issues

[Tejun Heo <htejun@gmail.com>]

Kalra Ashish-B00888 wrote:
> Hello Tejun,
> 
> This patch will surely fix my problem, but won't it be better to set
> each PMP device port link speed directly to
> the host<->PMP link speed, during SATA PMP device configuration in
> sata_pmp_attach(), instead of calling 
> sata_link_init_spd() for each link. 
> 
> The PMP chip should be responsible for matching link speed difference,
> but probably there could be issues with
> certain PMP chips, as it looks like in our case, where NCQ hangs are
> probably caused due to link speed difference.
> It should be simpler to handle it in S/W, by limiting PMP device port
> link speeds to host<->PMP link speed.

Yeah, I agree.  There's nearly nothing to be gained by driving
downstream PHYs faster than the upstream PHY.  I'll submit a patch to
limit downstream port speed by upstream speed.

Thanks.

-- 
tejun