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From: Tejun Heo <tj@kernel.org>
To: Kevin Hao <haokexin@gmail.com>
Cc: linux-ide@vger.kernel.org, Dan Williams <dan.j.williams@intel.com>
Subject: Re: [PATCH 4/5] libata: support the ata host which implements a queue depth less than 32
Date: Fri, 4 Jul 2014 11:30:22 -0400	[thread overview]
Message-ID: <20140704153022.GA764@mtj.dyndns.org> (raw)
In-Reply-To: <20140704064646.GA15828@pek-khao-d1.corp.ad.wrs.com>

Hello, Kevin.

On Fri, Jul 04, 2014 at 02:46:46PM +0800, Kevin Hao wrote:
> Since the fsl sata only support a 16 command queue, if we put the internal
> command to ata_port->qcmd[16 - 1], we can easily change the above code to:

Hmmm... something that I wanna do is using all 32 tags for regular
commands and moving ATA_TAG_INTERNAL to something out-of-bounds, say
32 or INT_MAX and let each driver use whatever command slot (most
likely zero) to actually execute internal commands.

There really is no reason to permanently reserve a command tag for
internal commands like we do now; however, it could be that using a
tag number to distinguish an internal command isn't a very good idea
to begin with and it could be better to use a qcflag instead.

Anyways, sata_fsl already has workaround for ATA_TAG_INTERNAL, right?
Given that the situation around internal tag handling may change, I'm
not sure about changing the interface now.  Is it a lot of cruft on
fsl side?

Thanks.

-- 
tejun

  reply	other threads:[~2014-07-04 15:30 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-03 12:09 [PATCH 0/5] libata: support the ata host which implements a queue depth less than 32 Kevin Hao
2014-07-03 12:09 ` [PATCH 1/5] libata: using ata_tag_internal() instead of open-coding Kevin Hao
2014-07-03 12:09 ` [PATCH 2/5] libata: introduce ata_get_internal_tag() Kevin Hao
2014-07-03 12:09 ` [PATCH 3/5] libata: add a 'struct ata_port *' argument for the ata tag help functions Kevin Hao
2014-07-03 12:09 ` [PATCH 4/5] libata: support the ata host which implements a queue depth less than 32 Kevin Hao
2014-07-03 13:47   ` Tejun Heo
2014-07-04  6:46     ` Kevin Hao
2014-07-04 15:30       ` Tejun Heo [this message]
2014-07-05 13:21         ` Kevin Hao
2014-07-05 20:00           ` Tejun Heo
2014-07-06  4:16             ` Kevin Hao
2014-07-03 13:50   ` Tejun Heo
2014-07-04  6:50     ` Kevin Hao
2014-07-03 12:09 ` [PATCH 5/5] sata_fsl: set the correct queue depth for the host controller Kevin Hao

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