Re: [PATCH v4 3/6] thermal: Added Bang-bang thermal governor

Zhang Rui
2014-07-21T09:37:15Z

On Mon, 2014-07-21 at 11:29 +0200, Borislav Petkov wrote:
> On Sun, Jul 20, 2014 at 02:51:17AM +0200, Peter Feuerer wrote:
> > The bang-bang thermal governor uses a hysteresis to switch abruptly on
> > or off a cooling device. It is intended to control fans, which can
> > not be throttled but just switched on or off.
> > Bang-bang cannot be set as default governor as it is intended for
> > special devices only. For those special devices the driver needs to
> > explicitely request it.
> >
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Zhang Rui <rui.zhang@intel.com>
> > Cc: Andreas Mohr <andi@lisas.de>
> > Cc: Borislav Petkov <bp@suse.de>
> > Cc: Javi Merino <javi.merino@arm.com>
> > Signed-off-by: Peter Feuerer <peter@piie.net>

For thermal related patches, please do cc linux-pm mailing list so that
I can see them in patchwork.

thanks,
rui
> > ---
> > drivers/thermal/Kconfig | 10 +++
> > drivers/thermal/Makefile | 1 +
> > drivers/thermal/gov_bang_bang.c | 131 ++++++++++++++++++++++++++++++++++++++++
> > drivers/thermal/thermal_core.c | 5 ++
> > drivers/thermal/thermal_core.h | 8 +++
> > 5 files changed, 155 insertions(+)
> > create mode 100644 drivers/thermal/gov_bang_bang.c
> >
> > diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> > index f9a1386..cdddf09 100644
> > --- a/drivers/thermal/Kconfig
> > +++ b/drivers/thermal/Kconfig
> > @@ -84,6 +84,16 @@ config THERMAL_GOV_STEP_WISE
> > Enable this to manage platform thermals using a simple linear
> > governor.
> >
> > +config THERMAL_GOV_BANG_BANG
> > + bool "Bang Bang thermal governor"
> > + default y
>
> Right, this is problematic.
>
> When people are faced with the new selection after doing oldconfig, they
> can say yes or no.
>
> However, as acerhdf depends on it now, prompting the user to
> unconditionally says yes is kinda redundant. Especially as this governor
> is not supposed to be default anyway.
>
> Actually you don't need the Kconfig prompt at all as this is a sort-of
> "internal" governor and devices select it. IOW, it should be "default n"
> and ACERHDF will do "select THERMAL_GOV_BANG_BANG". Something like that
> at least.
>