Re: AHCI problem with hotplug

[Robert Hancock <hancockr@shaw.ca>]

Tony Battersby wrote:
> Tejun Heo wrote:
>> Tony Battersby wrote:
>>   
>>> I am having a problem getting Linux to detect hot-plugged SATA disks on my
>>> ICH7 AHCI controller (SuperMicro PDSME motherboard).  On any SATA port that
>>> already had a disk plugged in during BIOS POST, Linux will see the disk and
>>> detect hot-plug and hot-unplug events just fine.  On any SATA port that did
>>> not have a disk plugged in during BIOS POST, Linux will not see a disk no
>>> matter what.  Here are the different sequences of events that I have tried:
>>>
>>> 1) boot with SATA disk plugged in
>>>    modprobe ahci: disk detected
>>>    unplug disk:   disk deleted
>>>    plug in disk:  disk detected
>>>
>>> 2) boot with SATA disk plugged in
>>>    unplug disk
>>>    modprobe ahci
>>>    plug in disk: disk detected
>>>    unplug disk:  disk deleted
>>>    plug in disk: disk detected
>>>    unplug disk:  disk deleted
>>>    plug in disk to any other SATA port    -> not detected
>>>    plug in disk to the original SATA port -> disk detected
>>>
>>> 3) boot with SATA disk unplugged
>>>    plug in disk to any SATA port
>>>    modprobe ahci: not detected
>>>    grep ahci /proc/interrupts: 0 interrupts
>>>
>>> 4) boot with SATA disk unplugged
>>>    modprobe ahci
>>>    plug in disk to any SATA port: not detected
>>>    grep ahci /proc/interrupts: 0 interrupts
>>>
>>> 5) keep SATA disk plugged in during BIOS POST but unplug it before the
>>>    kernel boots
>>>    kernel hangs at "BIOS data check"
>>>
>>> I have tried both 2.6.24.7 and 2.6.27.8 with the same result.
>>>
>>> The BIOS is configured as follows:
>>> Parallel ATA:         [Enabled]
>>> Serial ATA:           [Enabled]
>>> SATA Controller Mode: [Enhanced]
>>> SATA RAID:            [Disabled]
>>> SATA AHCI:            [Enabled]
>>>
>>> The root filesystem is on a parallel IDE disk using the legacy (non-libata)
>>> piix driver.
>>>     
>> The BIOS could be tristating the ports.  Does it work if you issue
>> manual rescan (echo - - - > /sys/class/scsi_host/hostN/scan)?
>>
>>   
> No luck.  I get:
> 
> ata1: hard resetting link
> ata1: SATA link down (SStatus 0 SControl 0)
> ata1: EH complete
> 
> And the drive isn't seen.

Well, if the controller reports link down there likely isn't much the 
kernel can do about it. I assume that ata1 is in fact where that drive 
gets detected if it's plugged in at boot - you could try all the other 
hosts to be sure..