From: Tejun Heo <tj@kernel.org>
To: Loc Ho <lho@apm.com>
Cc: Olof Johansson <olof@lixom.net>, Arnd Bergmann <arnd@arndb.de>,
Linux SCSI List <linux-scsi@vger.kernel.org>,
"linux-ide@vger.kernel.org" <linux-ide@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Don Dutile <ddutile@redhat.com>, Jon Masters <jcm@redhat.com>,
"patches@apm.com" <patches@apm.com>, Tuan Phan <tphan@apm.com>,
Suman Tripathi <stripathi@apm.com>
Subject: Re: [PATCH v13 2/3] ata: Add APM X-Gene SoC AHCI SATA host controller driver
Date: Mon, 24 Feb 2014 20:40:48 -0500 [thread overview]
Message-ID: <20140225014048.GA3450@htj.dyndns.org> (raw)
In-Reply-To: <CAPw-ZT=VHj+fO-7+G6Zdx+T+osJhXaR9AYHbx_TbWFWHBiDKYg@mail.gmail.com>
Hey,
On Mon, Feb 24, 2014 at 05:02:52PM -0800, Loc Ho wrote:
> The completion of the RAM removal from shutdown is quite fast. As per
> spec, the max time is 1ms but from the run-time code, it only take one
> (1us) or two (2us) read for this to completed. An 1 ms hard delay is more
> than 100 time slower. The code isn't that complex. If you strongly advise
> that I should remove the while loop and use 1 ms, then okay. Otherwise, I
> would prefer to keep the original code.
The code is rather silly because as it's written the delay may be upto
100ms. If it's sitting in the hot path, using things like
usleep_range() makes sense. In probe / shutdown paths, it's just an
unnecessary distraction. If the timeout is as short as 1ms, it
doesn't really matter whether the hardware can do it faster or not.
It's just irrelevant. Please just write simple code.
Thanks.
--
tejun
prev parent reply other threads:[~2014-02-25 1:40 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-24 5:54 [PATCH v13 0/3] ata: Add APM X-Gene SoC AHCI SATA host controller support Loc Ho
2014-02-24 5:54 ` [PATCH v13 1/3] Documentation: Add documentation for APM X-Gene SoC SATA host controller DTS binding Loc Ho
2014-02-24 5:54 ` [PATCH v13 2/3] ata: Add APM X-Gene SoC AHCI SATA host controller driver Loc Ho
2014-02-24 5:54 ` [PATCH v13 3/3] arm64: Add APM X-Gene SoC AHCI SATA host controller DTS entries Loc Ho
2014-02-24 18:32 ` Tejun Heo
[not found] ` <CAPw-ZT=CNdGn_iPp+jJbymvgBTNpXe1nCLeNwPWBdD3AAnHE6A@mail.gmail.com>
2014-02-25 5:54 ` Kishon Vijay Abraham I
2014-02-25 6:08 ` Loc Ho
2014-02-24 18:31 ` [PATCH v13 2/3] ata: Add APM X-Gene SoC AHCI SATA host controller driver Tejun Heo
[not found] ` <CAPw-ZT=VHj+fO-7+G6Zdx+T+osJhXaR9AYHbx_TbWFWHBiDKYg@mail.gmail.com>
2014-02-25 1:40 ` Tejun Heo [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140225014048.GA3450@htj.dyndns.org \
--to=tj@kernel.org \
--cc=arnd@arndb.de \
--cc=ddutile@redhat.com \
--cc=devicetree@vger.kernel.org \
--cc=jcm@redhat.com \
--cc=lho@apm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-ide@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=olof@lixom.net \
--cc=patches@apm.com \
--cc=stripathi@apm.com \
--cc=tphan@apm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).