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From: Matthew Garrett <matthew.garrett-05XSO3Yj/JvQT0dZR+AlfA@public.gmane.org>
To: "prarit-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org"
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Cc: "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
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	<mstowe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
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	<linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH RFC] i2c algo, Add i2c-algo-i801 driver [v1]
Date: Wed, 9 Apr 2014 17:59:03 +0000	[thread overview]
Message-ID: <1397066342.5276.21.camel@x230> (raw)
In-Reply-To: <53458992.4060003-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

On Wed, 2014-04-09 at 13:55 -0400, Prarit Bhargava wrote:
> 
> On 04/09/2014 01:37 PM, Matthew Garrett wrote:
> > Right. It's dangerous, which is why we forbid it by default. How do we
> > benefit from having a driver that's no safer?
> 
> We have yet to see where the existing case exhibits the behaviour of a race.  In
> fact, AFAICT, all we've seen is stability.  So it's no safer?  Yep.  It's as
> equally not racy as the existing workaround.

So... why add the driver at all? Refusing to permit the kernel to touch
these resources is a deliberate design choice, because of the potential
for these races. It'll work absolutely fine right up until the point
where you end up reading the wrong temperature value from an i2c hwmon
chip and perform a critical thermal shutdown.

-- 
Matthew Garrett <matthew.garrett@nebula.com>

  parent reply	other threads:[~2014-04-09 17:59 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-09 16:22 [PATCH RFC] i2c algo, Add i2c-algo-i801 driver [v1] Prarit Bhargava
     [not found] ` <1397060563-30431-1-git-send-email-prarit-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-04-09 16:36   ` Matthew Garrett
2014-04-09 17:02     ` Prarit Bhargava
     [not found]       ` <53457D0D.7020805-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-04-09 17:09         ` Matthew Garrett
2014-04-09 17:34           ` Prarit Bhargava
     [not found]             ` <5345849F.6070909-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-04-09 17:37               ` Matthew Garrett
2014-04-09 17:55                 ` Prarit Bhargava
     [not found]                   ` <53458992.4060003-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-04-09 17:59                     ` Matthew Garrett [this message]
2014-04-09 18:02                       ` Prarit Bhargava
     [not found]                         ` <53458B2A.30003-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-04-09 18:27                           ` Matthew Garrett
2014-04-09 19:22                       ` Jean Delvare
2014-04-09 19:24                         ` Matthew Garrett
2014-04-09 19:01           ` Jean Delvare
2014-04-09 19:05             ` Matthew Garrett
2014-04-10 19:15           ` Prarit Bhargava
2014-04-10 20:26             ` Matthew Garrett
2014-04-11 17:47               ` Prarit Bhargava
     [not found]                 ` <53482AC2.2060605-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-04-11 18:55                   ` Matthew Garrett
2014-04-09 18:56     ` Jean Delvare
2014-04-09 18:58       ` Matthew Garrett
2014-04-09 20:25         ` Jean Delvare
2014-04-09 16:37   ` Jean Delvare
2014-04-09 16:57     ` Prarit Bhargava
     [not found]       ` <53457C00.1030400-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2014-04-09 20:27         ` Jean Delvare

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