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From: Tejun Heo <htejun@gmail.com>
To: Mark Lord <liml@rtr.ca>
Cc: Matthew Wilcox <matthew@wil.cx>,
	linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: ata_ram driver
Date: Thu, 06 Mar 2008 17:21:58 +0900	[thread overview]
Message-ID: <47CFA9A6.2040506@gmail.com> (raw)
In-Reply-To: <47BF3E54.9050609@rtr.ca>

Mark Lord wrote:
> Matthew Wilcox wrote:
>> I've ported the scsi_ram driver [1] to libata.  It could use a lot more
>> work -- there's a lot of stuff in the identify page that I haven't
>> filled in, and there's a lot of commands it doesn't even try to execute.
>>
>> For example, when you unload the driver, you get the mildly disturbing
>> messages:
>>
>> sd 12:0:0:0: [sdb] Stopping disk
>> sd 12:0:0:0: [sdb] START_STOP FAILED
>> sd 12:0:0:0: [sdb] Result: hostbyte=DID_BAD_TARGET
>> driverbyte=DRIVER_OK,SUGGEST_OK
>>
> ..
> 
> I see messages like those with *established* libata drivers from time to
> time.
> It could just be a bug in the shutdown sequence, somewhere between libata,
> SCSI, block layer, and the device model in general.  Or not.

It's because of the sequence of events.  Currently, driver unload
sequence is the same as when the device is hot unplugged.  libata
detects that the device is gone and disables it and report it to SCSI
layer.  SCSI layer takes over and tries to kill the SCSI device and tell
sd to shutdown and sd issues START_STOP to shutdown which fails w/
DID_BAD_TARGET because the matching ATA device is already gone.  I've
left it that way because I'm not sure whether spinning down the drive on
driver unload is the correct thing to do.  The message is annoying tho.

Thanks.

-- 
tejun

  reply	other threads:[~2008-03-06  8:22 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-22 20:09 Matthew Wilcox
2008-02-22 21:27 ` Mark Lord
2008-03-06  8:21   ` Tejun Heo [this message]
2008-03-06 15:28     ` James Bottomley
2008-03-06 23:55       ` Tejun Heo
2008-03-07  0:01         ` James Bottomley
2008-03-07  0:13           ` Tejun Heo
2008-03-07  0:22             ` James Bottomley
2008-03-07  0:28               ` Tejun Heo
2008-03-07  0:39                 ` James Bottomley
2008-03-07  0:43                   ` Tejun Heo
2008-03-07  3:08                     ` [PATCH 1/2] scsi: export scsi_forget_host() Tejun Heo
2008-03-07  3:11                       ` [PATCH 2/2] libata: kill SCSI devices before detaching ata_host Tejun Heo
2008-03-07  2:16                 ` ata_ram driver Jeff Garzik
2008-03-07  2:44                   ` James Bottomley

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