Messages in this thread | | | Subject | Re: [PATCH v3 3/4] thermal/core: Build ascending ordered indexes for the trip points | From | Zhang Rui <> | Date | Tue, 19 Jul 2022 22:17:20 +0800 |
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On Tue, 2022-07-19 at 09:22 +0200, Daniel Lezcano wrote: > On 19/07/2022 03:14, Zhang Rui wrote: > > On Mon, 2022-07-18 at 15:21 +0200, Daniel Lezcano wrote: > > > > > > Hi Zhang, > > > > > > thanks for the review > > > > > > On 18/07/2022 07:28, Zhang Rui wrote: > > > > On Fri, 2022-07-15 at 23:09 +0200, Daniel Lezcano wrote: > > > > > > [ ... ] > > > > > > > > Instead of taking the risk of breaking the existing > > > > > platforms, > > > > > use an > > > > > array of temperature ordered trip identifiers and make it > > > > > available > > > > > for the code needing to browse the trip points in an ordered > > > > > way. > > > > > > > > > > Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> > > > > > --- > > > > > > [ ... ] > > > > > > > > +static void sort_trips_indexes(struct thermal_zone_device > > > > > *tz) > > > > > +{ > > > > > + int i, j; > > > > > + > > > > > + for (i = 0; i < tz->trips; i++) > > > > > + tz->trips_indexes[i] = i; > > > > > + > > > > > + for (i = 0; i < tz->trips; i++) { > > > > > + for (j = i + 1; j < tz->trips; j++) { > > > > > + int t1, t2; > > > > > + > > > > > + tz->ops->get_trip_temp(tz, tz- > > > > > > trips_indexes[i], &t1); > > > > > > > > This line can be moved to the upper loop. > > > > > > Right, thanks! > > > > > > > > + tz->ops->get_trip_temp(tz, tz- > > > > > > trips_indexes[j], &t2); > > > > > + > > > > > > > > what about the disabled trip points? > > > > > > > > we should ignore those trip points and check the return value > > > > to > > > > make > > > > sure we're comparing the valid trip_temp values. > > > > > > We don't have to care about, whatever the position, the > > > corresponding > > > trip id will be disabled by the trip init function before calling > > > this > > > one and ignored in the handle_thermal_trip() function > > > > hah, I missed this one and replied to your latest reply directly. > > > > The thing I'm concerning is that if we don't check the return > > value, > > for a disabled trip point, the trip_temp (t1/t2) returned is some > > random value, it all depends on the previous value set by last > > successful .get_trip_temp(), and this may screw up the sorting. > > The indexes array is the same size as the trip array, that makes the > code much less prone to errors. > > To have the same number of trip points, the index of the disabled > trip > must be inserted also in the array. We don't care about its position > in > the indexes array because it is discarded in the handle_trip_point() > function anyway. For this reason, the random temperature of the > disabled > trip point and the resulting position in the sorting is harmless. > > It is made on purpose to ignore the return value, so we have a > simpler code. > Let's take below case for example, say, we have three trip points 0, 1, 2, and trip point 1 is broken and disabled.
trip temp for trip point 0 is 10 and for trip point 2 is 20. .get_trip_temp(tz, 1, &t) fails, and t is an uninitialized random value
Initial: trip_indexes[0]=0,trip_indexes[1]=1,trip_indexes[2]=2 step1: i=0,j=1 get trip temp for trip point trip_indexes[0]=0 and trip_indexes[1]=1 trip point 1 returns trip temp 5, and it swaps with trip point 0 so trip_indexes[0]=1,trip_indexes[1]=0,trip_indexes[2]=2 step2: i=0,j=2 get trip temp for trip point trip_indexes[0]=1 and trip_indexes[2]=2 trip point 1 returns trip temp 25, and it swaps with trip point 2 so trip_indexes[0]=2,trip_indexes[1]=0,trip_indexes[2]=1
And the sorting is broken now.
please correct me if I'm missing anything.
thanks, rui
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