From: Jonathan Cameron <jic23@cam.ac.uk>
To: Grant Grundler <grundler@google.com>
Cc: Dan Carpenter <error27@gmail.com>,
linux-iio@vger.kernel.org, devel@driverdev.osuosl.org
Subject: Re: STAGING:iio:light: fix ISL29018 init to handle brownout
Date: Tue, 30 Aug 2011 17:31:19 +0100 [thread overview]
Message-ID: <4E5D1057.3020706@cam.ac.uk> (raw)
In-Reply-To: <CANEJEGsohYnKXNUKUSfBpXofcNdt13bY_mnFZRUWMpewNjUykg@mail.gmail.com>
On 08/30/11 17:14, Grant Grundler wrote:
> On Tue, Aug 30, 2011 at 3:05 AM, Jonathan Cameron <jic23@cam.ac.uk> wrote:
> ....
>>> I did change one basic behavior that I think was also broken: cache
>>> the value regardless of if the transaction completed successfully or
>>> not.
>> Don't do that. That means userspace will get an invalid value if it reads
>> in the meantime. If you have an error on a hardware bus - tell userspace about
>> it and don't 'guess' what is in the register.
>
> Ah ok - I didn't know this was part of the path to/from user space.
It plausibly isn't, I didn't go over it closely enough to be sure.
Even if not, it's a nasty complexity that will bite someone at some stage.
Mostly comes down to code doing what other code does in the same situation
rather than trying to be clever.
>
>>
>> Otherwise patch looks fine to me.
>
> OK - I'll restore previous behavior and submit another patch.
>
> cheers!
> grant
>
next prev parent reply other threads:[~2011-08-30 16:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-26 1:15 STAGING:iio:light: fix ISL29018 init to handle brownout Dan Carpenter
2011-08-26 5:27 ` Grant Grundler
2011-08-26 21:58 ` Grant Grundler
2011-08-26 22:18 ` Dan Carpenter
2011-08-26 22:42 ` Grant Grundler
2011-08-30 10:05 ` Jonathan Cameron
2011-08-30 16:14 ` Grant Grundler
2011-08-30 16:31 ` Jonathan Cameron [this message]
2011-08-30 16:45 ` Grant Grundler
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=4E5D1057.3020706@cam.ac.uk \
--to=jic23@cam.ac.uk \
--cc=devel@driverdev.osuosl.org \
--cc=error27@gmail.com \
--cc=grundler@google.com \
--cc=linux-iio@vger.kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.