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    SubjectRe: [PATCH v4 3/6] thermal: Added Bang-bang thermal governor
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    Hi,

    Zhang Rui writes:

    > 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>
    >> > ---
    >> > 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.
    >>
    > I agree with this approach.

    Yes, you are right, this looks better. Then the "depend on
    THERMAL_GOV_BANG_BANG" could be removed from acerhdf Kbuild, as the "select"
    will take care acerhdf is compiled with THERMAL_GOV_BANG_BANG enabled,
    right?

    --
    --peter;


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