Hi Javi,
Javi Merino writes:
Hi Peter,
On Sat, May 03, 2014 at 06:59:24PM +0100, Peter Feuerer wrote:
acerhdf has been doing an on-off fan control using hysteresis by
post-manipulating the outcome of thermal subsystem trip point handling.
This patch enables acerhdf to use the bang-bang governor, which is
intended for on-off controlled fans.
Cc: Andrew Morton <[email protected]>
CC: Zhang Rui <[email protected]>
Cc: Andreas Mohr <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Javi Merino <[email protected]>
Signed-off-by: Peter Feuerer <[email protected]>
---
drivers/platform/x86/Kconfig | 2 +-
drivers/platform/x86/acerhdf.c | 34 +++++++++++++++++++++++++++++-----
2 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 27df2c5..0c15d89 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -38,7 +38,7 @@ config ACER_WMI
config ACERHDF
tristate "Acer Aspire One temperature and fan driver"
- depends on THERMAL && ACPI
+ depends on ACPI && THERMAL_GOV_BANG_BANG
---help---
This is a driver for Acer Aspire One netbooks. It allows to access
the temperature sensor and to control the fan.
diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
index 176edbd..afaa849 100644
--- a/drivers/platform/x86/acerhdf.c
+++ b/drivers/platform/x86/acerhdf.c
@@ -50,7 +50,7 @@
*/
#undef START_IN_KERNEL_MODE
-#define DRV_VER "0.5.30"
+#define DRV_VER "0.5.31"
/*
* According to the Atom N270 datasheet,
@@ -259,6 +259,14 @@ static const struct bios_settings_t bios_tbl[] = {
static const struct bios_settings_t *bios_cfg __read_mostly;
+/*
+ * this struct is used to instruct thermal layer to use bang_bang instead of
+ * default governor for acerhdf
+ */
+static struct thermal_zone_params acerhdf_zone_params = {
+ .governor_name = "bang_bang",
+};
+
static int acerhdf_get_temp(int *temp)
{
u8 read_temp;
@@ -440,6 +448,15 @@ static int acerhdf_get_trip_type(struct
thermal_zone_device *thermal, int trip,
return 0;
}
+static int acerhdf_get_trip_hyst(struct thermal_zone_device *thermal, int trip,
+ unsigned long *temp)
+{
+ if (trip == 0)
+ *temp = fanon - fanoff;
+
+ return 0;
+}
+
I think you should only return 0 if you've updated the temperature.
Otherwise you're telling the calling function that everything went all
right but you may be leaving garbage in *temp. What about
if (trip != 0)
return -EINVAL;
*temp = fanon - fanoff;
return 0;
Yes, sounds good. What about trip == 1? This is a valid trip point for
acerhdf (critical) and one could argue, that it has a valid hysteresis of
0. - Thus EINVAL would be wrong here.
thanks and kind regards,
--peter;
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