Subject: Re: Making a common API for cpu frequency drivers
To: Jachym Holecek <freza@dspfpga.com>
From: Juan RP <juan@xtrarom.org>
List: tech-kern
Date: 09/04/2006 00:44:45
On Mon, 4 Sep 2006 00:38:50 +0200
Jachym Holecek <freza@dspfpga.com> wrote:

> Hello,
> 
> [Err, forgot to group-reply previously...]
> 
> # Juan RP 2006-09-03:
> > I have the following code:
> > 
> > http://www.xtrarom.org/~juan/sysmon_cpufreq/cpufreq.diff <- kernel
> > part http://www.xtrarom.org/~juan/sysmon_cpufreq/dict_kern.c <-
> > userland
> 
> Shouldn't SMCPUFREQ_GDICT be _IOWR? You want to copy plistref into
> the kernel to get valid size & userland pointer so that you know
> where to copyout() the externalized dict. For this, _IOW is enough
> but it seems you also need the R bit (see
> common/lib/libprop/prop_kern.c) to read back real size of
> externalized form.

Oh yeah. Cube just explained the same to me with details.

Thank you very much to both.