Re: eSATA Drive Detection issues on mvsas

[Praveen Murali <pmurali@logicube.com>]

Dan/James,
  Can you please take a look at this and let me know if I am at the 
right place? Or point me in the right direction? As I understand, this 
deost not look like an mvsas driver issue.

Thanks,
Praveen

On 10/14/2013 05:18 PM, Praveen Murali wrote:
> Hi,
>   I have couple of external drives (Western Digital and Seagate) that 
> have an eSATA interface. My Linux box with a Marvell HBA (9445) 
> running Ubuntu 12.04 with 3.2.48 kernel doest not seem to detect the 
> drive. I tried with the latest upstream kernel and it behaves the 
> same. But both the drives detect fine if I enter the mvsas BIOS during 
> bootup. So I have hooked up a SATA analyzer and this is what I found
> - When I tried to detect the drives in the mvsas BIOS, all the ATA 
> commands that the bios issues have the port multiplier byte set to 0.
> - If I bootup my Linux system and then connect the drives, the first 
> IDENTIFY command has the port multiplier set to 0 (this one is 
> successful) and the subsequent IDENTIFY command has port multiplier 
> set to 1 (this one fails).
> - If I connect any other SATA drives I have to the HBA, all the ATA 
> commands have port multiplier set to 1 but they detects and work fine.
>
> Just to rule out the port-multiplier possibility I changed the 
> following line in drivers/scsi/libsas/sas_ata.c - fucntion 
> sas_ata_qc_issue()
>
> ata_tf_to_fis(&qc->tf, 1, 0, (u8*)&task->ata_task.fis);
>
> to
>
> ata_tf_to_fis(&qc->tf, 0, 0, (u8*)&task->ata_task.fis);
>
> now all my drives seem to detect just fine. I believe, the eSATA 
> interface on these external drives is a port multiplier, which is why 
> the command fails. Also, the normal drives ignore this field thats why 
> they work fine with port multiplier being set to either 0 or 1.
>
> Question(s): Are my above assumtions correct? If so, what is the 
> reasoning behind setting the port multiplier to 1 by default in libsas 
> layer?
>
> Thanks,
> Praveen
>
>
>
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