RE: [PATCH] [SCSI] LIBSAS: fix libsas link error issue

[Xiangliang Yu]

Subject: Re: [PATCH] [SCSI] LIBSAS: fix libsas link error issue

On Tue, 2011-06-14 at 23:17 +0800, yxlraid@xxxxxxxxx wrote:
>> From: Xiangliang Yu <yuxiangl@xxxxxxxxxxx>
>> 
>> -- The value of child link rate should is minimum of link rate, or
>>    command will fail if child link rate is bigger than parent link rate.
>> 
>> Signed-off-by: Xiangliang Yu <yuxiangl@xxxxxxxxxxx>
>> ---
>>  drivers/scsi/libsas/sas_expander.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>> 
>> diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
>> index 874e29d..6ccca09 100644
>> --- a/drivers/scsi/libsas/sas_expander.c
>> +++ b/drivers/scsi/libsas/sas_expander.c
>> @@ -638,7 +638,7 @@ static void sas_ex_get_linkrate(struct domain_device *parent,
>>  			sas_port_add_phy(port, phy->phy);
>>  		}
>>  	}
>> -	child->linkrate = min(parent_phy->linkrate, child->max_linkrate);
>> +	child->linkrate = min(parent_phy->linkrate, child->min_linkrate);

>This patch doesn't look right.  It will clamp the phy to the minim
>possible link rate.  
Link negotiation should get the minimum.

>The child is supposed to support everywhere between
>child->min_linkrate and child->max_linkrate.  The reason why we pick the
>max is because we should use that if the parent supports it, and fall
>back only if the parent isn't capable.
Now, the problem is command fail, and LIBSAS seem to do nothing.
Do you mean drive need to fix the link error?
Thanks!

PS: The Kernel will panic when link error happening.

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