Re: port multiplier problem

[Grant Grundler <grundler@google.com>]

On Tue, Feb 2, 2010 at 11:22 AM, Chandra Shekhar Sah <edu4madh@gmail.com> wrote:
> Hi Grant,
>
> Thank for reply.
> Yes, PMP is sil3726. The backplane of the disk array has two PMP (each
> 1-to-5 as you have mentioned) and two sata direct connection without PMP.
> So, 10 disk are behind 2 PMP.

Ah ok. That explains your "5-5-1-1" comment now. I tried to find a
Data sheet for this board but only found one in Chinese:
    www.norco.com.cn/UpLoadFile/Manual/DS-12X0-CN.pdf

and I unfortunately don't speak/read chinese. Probably doesn't matter
though since...

This email thread looks like a duplicate of a previous bug report:
   http://markmail.org/message/lp3ynvfefejpiy2r

(or search for  "Ubuntu 9.04 (2.6.28-14) and eSATA Port Multiplier
(PMP) Not working")

Chandra, you might read through that thread and dmesg output (posted by Chris K)
to see what else you have in common.

I had two questions on that thread that never got answered:
   http://markmail.org/message/snpekoj4qexrslk5

| How can we find out if anyone has the SEMB properly wired up?
| Would it be hard to make libata aware of "SEMB port not responding" case?
| ie if the SEMB port times out or has no link, reduce the port count of
| the sil3726 PMP by one.
|
| Maybe add a "enable_sil24_semb" flag to libata?
| (avoid checking unless someone asks for it). I hate magic flags but also
| don't want to subject most people to the timeout delay.

I (or Gwendal) can post a patch (and lightly test) for any of the above.
Just need to get some guidance so we don't waste our time.

thanks,
grant

> Total is 12 disks. The sata host controller is
> sil3124. Picture of the backplane is attached.
>
> Thanks,
> Chandra
>
> On 2/2/10 2:04 PM, Grant Grundler wrote:
>>
>> On Tue, Feb 2, 2010 at 10:12 AM, Chandra Shekhar Sah<edu4madh@gmail.com>
>>  wrote:
>>
>>>
>>> Hi Grant,
>>>
>>> There are 6 Seagate Barracuda and 6 Hitachi DeskStar.
>>>
>>
>> I thought 0x1095/0x3726 was a Silicon Image part. Can you confirm this?
>>
>> If it is, this sounds like a broken implementation to me. Here is what
>> the Silicon Image 3726 Data Sheet says in the introduction:
>>     Silicon Image’s SiI3726 is 1-to-5 SATA Port Multiplier designed to
>> provide a high performance link between a single SATA host port and 5
>> SATA device ports.
>>
>> So I don't know where the 6th device is getting connected. Some
>> explanation/data sheet from the HW vendor would be helpful at this
>> point.
>>
>>
>>>
>>> Seagate Model: ST3750640AS
>>> Firmware: 3.AAK
>>>
>>> Hitachi Model:HDS721075KLA330
>>> Firmware: Not sure
>>>
>>
>> Both of these drives work behind Sil3726. (First hand experience).
>>
>>
>>>
>>> I have attached pictures of both labels, in case.
>>>
>>
>> Perfect - thanks for posting those.
>>
>> thanks,
>> grant
>>
>>
>
>