Re: [PATCH 2/6] scsi: hisi_sas: workaround a SoC SATA IO processing bug

[Johannes Thumshirn <jthumshirn@suse.de>]

On Mon, Apr 10, 2017 at 09:21:57PM +0800, John Garry wrote:
> From: Xiaofei Tan <tanxiaofei@huawei.com>
> 
> This patch provides a workaround a SoC bug where SATA IPTTs for
> different devices may conflict.
> 
> The workaround solution requests the following:
> 1. SATA device id must be even and not equal to SAS IPTT.
> 2. SATA device can not share the same IPTT with other SAS or
> SATA device.
> 
> Besides we shall consider IPTT value 0 is reserved for another SoC
> bug (STP device open link at firstly after SAS controller reset).
> 
> To sum up, the solution is:
> Each SATA device uses independent and continuous 32 even IPTT from
> 64 to 4094, then v2 hw can only support 63 SATA devices.
> All SAS device(SSP/SMP devices) share odd IPTT value from 1 to
> 4095.
> 
> Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---

Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
-- 
Johannes Thumshirn                                          Storage
jthumshirn@suse.de                                +49 911 74053 689
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