From: Simon Horman <horms@verge.net.au>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Liam Girdwood <lrg@ti.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] regulator: notify sysfs when voltage is set
Date: Thu, 15 Mar 2012 23:26:58 +0900 [thread overview]
Message-ID: <20120315142657.GD3129@verge.net.au> (raw)
In-Reply-To: <20120315124631.GJ3138@opensource.wolfsonmicro.com>
On Thu, Mar 15, 2012 at 12:46:31PM +0000, Mark Brown wrote:
> On Thu, Mar 15, 2012 at 09:04:33PM +0900, Simon Horman wrote:
>
> > This allows libudev to be used to monitor voltage changes and thus allows
> > user-space code to avoid polling the sysfs entry for changes.
>
> I notice that we don't generate similar events for cpufreq... what are
> the performance implications from firing off udev (which isn't free)
> every time we scale the CPU frequency? It feels like this might be
> disruptive, especially with a governor like ondemand which responds to
> system load.
Hi Mark,
that is a good point and to be honest not one that I had considered. For
the use-case that I have in mind, which is basically to log voltage changes
over time, it may be acceptable to rate-limit notifications somehow. But at
that point I may be better off just polling.
Out of interest, how often can ondemand potentially change the voltage?
next prev parent reply other threads:[~2012-03-15 14:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-15 12:04 [PATCH] regulator: notify sysfs when voltage is set Simon Horman
2012-03-15 12:46 ` Mark Brown
2012-03-15 14:26 ` Simon Horman [this message]
2012-03-15 14:47 ` Mark Brown
2012-03-15 23:23 ` Simon Horman
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