Re: [RFC PATCH] isci: filter broadcast change notifications during SMP phy resets

[Brian King <brking@linux.vnet.ibm.com>]

On 06/27/2011 09:34 AM, Hannes Reinecke wrote:
> On 06/24/2011 09:48 PM, Dan Williams wrote:
>> From: Jeff Skirvin<jeffrey.d.skirvin@intel.com>
>>
>> When resetting a sata device in the domain we have seen occasions where
>> libsas prematurely marks a device gone in the time it takes for the
>> device to re-establish the link.  This plays badly with software raid
>> arrays.  Other libsas drivers have non-uniform delays in their reset
>> handlers to try to cover this condition, but not sufficient to close the
>> hole.  Given that a sata device can take many seconds to recover we
>> filter bcns and poll for the device reattach state before notifying
>> libsas that the port needs the domain to be rediscovered.  Once this has
>> been proven out at the lldd level we can think about uplevelling this
>> feature to a common implementation in libsas.
>>
> That's the second time something like this have come up now.
> Wouldn't it makes sense to implement something like the dev_loss_tmo mechanism with have for FC? That should cover this situation nicely ...

Yes. This would help with some non FC multipath environments as well. It would be
nice to have dev_loss_tmo / fast_io_fail_tmo available independent of the
transport class. 

-Brian

-- 
Brian King
Linux on Power Virtualization
IBM Linux Technology Center