Messages in this thread | | | Date | Wed, 28 Sep 2022 13:52:50 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH] thermal: Increase maximum number of trip points |
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On Tue, Sep 27, 2022 at 09:17:09PM +0530, Sumeet Pawnikar wrote: > On one of the Chrome system, if we define more than 12 trip points, > probe for thermal sensor fails with > "int3403 thermal: probe of INTC1046:03 failed with error -22" > and throws an error as > "thermal_sys: Error: Incorrect number of thermal trips". > > The thermal_zone_device_register() interface needs maximum > number of trip points supported in a zone as an argument. > This number can't exceed THERMAL_MAX_TRIPS, which is currently > set to 12. To address this issue, THERMAL_MAX_TRIPS value > has to be increased. > > This interface also has an argument to specify a mask of trips > which are writable. This mask is defined as an int. > This mask sets the ceiling for increasing maximum number of > supported trips. With the current implementation, maximum number > of trips can be supported is 31. > > Also, THERMAL_MAX_TRIPS macro is used in one place only. > So, remove THERMAL_MAX_TRIPS macro and compare num_trips > directly with using a macro BITS_PER_TYPE(int)-1.
FWIW, Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Sumeet Pawnikar <sumeet.r.pawnikar@intel.com> > --- > drivers/thermal/thermal_core.c | 15 ++++++++++++++- > include/linux/thermal.h | 2 -- > 2 files changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c > index 50d50cec7774..589dd82fe10c 100644 > --- a/drivers/thermal/thermal_core.c > +++ b/drivers/thermal/thermal_core.c > @@ -1212,7 +1212,20 @@ thermal_zone_device_register_with_trips(const char *type, struct thermal_trip *t > return ERR_PTR(-EINVAL); > } > > - if (num_trips > THERMAL_MAX_TRIPS || num_trips < 0 || mask >> num_trips) { > + /* > + * Max trip count can't exceed 31 as the "mask >> num_trips" condition. > + * For example, shifting by 32 will result in compiler warning: > + * warning: right shift count >= width of type [-Wshift-count- overflow] > + * > + * Also "mask >> num_trips" will always be true with 32 bit shift. > + * E.g. mask = 0x80000000 for trip id 31 to be RW. Then > + * mask >> 32 = 0x80000000 > + * This will result in failure for the below condition. > + * > + * Check will be true when the bit 31 of the mask is set. > + * 32 bit shift will cause overflow of 4 byte integer. > + */ > + if (num_trips > (BITS_PER_TYPE(int) - 1) || num_trips < 0 || mask >> num_trips) { > pr_err("Incorrect number of thermal trips\n"); > return ERR_PTR(-EINVAL); > } > diff --git a/include/linux/thermal.h b/include/linux/thermal.h > index 1386c713885d..c05f5c78a0f2 100644 > --- a/include/linux/thermal.h > +++ b/include/linux/thermal.h > @@ -17,8 +17,6 @@ > #include <linux/workqueue.h> > #include <uapi/linux/thermal.h> > > -#define THERMAL_MAX_TRIPS 12 > - > /* invalid cooling state */ > #define THERMAL_CSTATE_INVALID -1UL > > -- > 2.17.1 >
-- With Best Regards, Andy Shevchenko
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