On Mon, 2013-02-04 at 11:49 -0800, amit daniel kachhap wrote: > On Thu, Jan 31, 2013 at 11:59 PM, Zhang Rui <rui.zh...@intel.com> wrote: > > On Thu, 2013-01-24 at 16:24 +0100, Gu1 wrote: > >> In different places in the Thermal code, the CPU frequency list is iterated > >> in an incorrect way, leading to endless loops when the frequency list > >> contains > >> a CPUFREQ_TABLE_INVALID entry, which is the case by default in the the > >> Exynos > >> 4x12 cpufreq driver, for example. > >> > >> The frequency list is iterated with a while loop, and when a > >> CPUFREQ_TABLE_INVALID entry is encountered, the continue; statement is > >> used to > >> skip it, but the index is not incremented, causing an endless loop. > >> > >> A similar bug was fixed by hongbo.zhang in commit: > >> Thermal: fix bug of counting cpu frequencies > >> > >> Signed-off-by: Gu1 <g...@aeroxteam.fr> > >> --- > >> drivers/thermal/cpu_cooling.c | 8 +++----- > >> drivers/thermal/exynos_thermal.c | 9 +++++---- > >> 2 files changed, 8 insertions(+), 9 deletions(-) > >> > >> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c > >> index 836828e..51acd26 100644 > >> --- a/drivers/thermal/cpu_cooling.c > >> +++ b/drivers/thermal/cpu_cooling.c > >> @@ -123,7 +123,7 @@ static int is_cpufreq_valid(int cpu) > >> */ > >> static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long > >> level) > >> { > >> - int ret = 0, i = 0; > >> + int ret = 0, i; > >> unsigned long level_index; > >> bool descend = false; > >> struct cpufreq_frequency_table *table = > >> @@ -131,7 +131,7 @@ static unsigned int get_cpu_frequency(unsigned int > >> cpu, unsigned long level) > >> if (!table) > >> return ret; > >> > >> - while (table[i].frequency != CPUFREQ_TABLE_END) { > >> + for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { > >> if (table[i].frequency == CPUFREQ_ENTRY_INVALID) > >> continue; > >> > >> @@ -145,7 +145,6 @@ static unsigned int get_cpu_frequency(unsigned int > >> cpu, unsigned long level) > >> /*return if level matched and table in descending order*/ > >> if (descend && i == level) > >> return table[i].frequency; > >> - i++; > >> } > >> i--; > >> > >> @@ -154,13 +153,12 @@ static unsigned int get_cpu_frequency(unsigned int > >> cpu, unsigned long level) > >> level_index = i - level; > >> > >> /*Scan the table in reverse order and match the level*/ > >> - while (i >= 0) { > >> + for (; i >= 0; i--) { > >> if (table[i].frequency == CPUFREQ_ENTRY_INVALID) > >> continue; > >> /*return if level matched*/ > >> if (i == level_index) > >> return table[i].frequency; > >> - i--; > >> } > >> return ret; > >> } > > > > so the "level" parameter is the index in the frequency table, right? > > > >> diff --git a/drivers/thermal/exynos_thermal.c > >> b/drivers/thermal/exynos_thermal.c > >> index 224751e..fa9e1d7 100644 > >> --- a/drivers/thermal/exynos_thermal.c > >> +++ b/drivers/thermal/exynos_thermal.c > >> @@ -233,7 +233,8 @@ static int exynos_get_crit_temp(struct > >> thermal_zone_device *thermal, > >> > >> static int exynos_get_frequency_level(unsigned int cpu, unsigned int freq) > >> { > >> - int i = 0, ret = -EINVAL; > >> + int i, ret = -EINVAL; > >> + unsigned int count = 0; > >> struct cpufreq_frequency_table *table = NULL; > >> #ifdef CONFIG_CPU_FREQ > >> table = cpufreq_frequency_get_table(cpu); > >> @@ -241,12 +242,12 @@ static int exynos_get_frequency_level(unsigned int > >> cpu, unsigned int freq) > >> if (!table) > >> return ret; > >> > >> - while (table[i].frequency != CPUFREQ_TABLE_END) { > >> + for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { > >> if (table[i].frequency == CPUFREQ_ENTRY_INVALID) > >> continue; > >> if (table[i].frequency == freq) > >> - return i; > >> - i++; > >> + return count; > >> + count++; > >> } > >> return ret; > >> } > > > > but we ignore the invalid entry here. > > > > take the following cpufreq table for example, with your patch, > > entry frequency > > 0 2.4G > > 1 invalid > > 2 2G > > 3 invalid > > 4 1.6G > > 5 end > > > > in exynos_get_frequency_level(), freq 1.6G is translated to level 2, > > because count is increased only twice, for entry 0 and entry 2, right? > > Hi Rui, > > Gui fixes looks fine for infinite loop issue. After Gui's fixes 1.6G > in translated to level 4 which is fine. > > Thanks, > Amit Daniel > > > > > but then, in get_cpu_frequency(), level 2 is translated to 2G HZ, which > > I do not think is what we want. > > > > I think we are doing something wrong here, and here is a cleanup patch I > > made > > to fix this issue, please review. > > > > From a868d68fdcd94a29ac9d3998283119a453decb4b Mon Sep 17 00:00:00 2001 > > From: Zhang Rui <rui.zh...@intel.com> > > Date: Fri, 1 Feb 2013 15:41:47 +0800 > > Subject: [PATCH] Thermal cpu_cooling: fix inconsistent use of CPU frequency > > table > > > > there are three kinds of entries in CPU frequency table. > > 1. invalid entry, its frequency is CPUFREQ_ENTRY_INVALID. > > 2. duplicate entry, two entry may share the same frequency, > > And we should treat it as on valid entry. > > 3. valid entry with a proper frequency. > > > > And when talking about cpufreq cooling device cooling state, > > it should be the same thing, in both cpu_cooling.c and its users, > > AKA, max_cooling_state of a cpufreq cooling device equals the > > number of VALID entries (type #3 above) in CPU frequency table. > > And when setting a cpufreq cooling device to state X, it means set > > the cpufreq cooling device to Xth maximum frequency in the > > cpufreq frequency table. > > > > This patch does a cleanup in both drivers/thermal/cpu_cooling.c > > and drivers/thermal/exynos_thermal.c to make them be consistent > > in using cpu level/cpufreq cooling state. > > > > Signed-off-by: Zhang Rui <rui.zh...@intel.com> > > --- > > drivers/thermal/cpu_cooling.c | 122 > > ++++++++++++++++++++++++-------------- > > drivers/thermal/exynos_thermal.c | 17 +----- > > include/linux/cpu_cooling.h | 12 ++++ > > 3 files changed, 91 insertions(+), 60 deletions(-) > > > > diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c > > index 836828e..c16795b 100644 > > --- a/drivers/thermal/cpu_cooling.c > > +++ b/drivers/thermal/cpu_cooling.c > > @@ -116,6 +116,40 @@ static int is_cpufreq_valid(int cpu) > > } > > > > /** > > + * cpufreq_cooling_get_max_level - function to get max valid cpufreq levels > > + * @cpu: cpu for which frequency is fetched. > > + */ > > +int cpufreq_cooling_get_max_level(unsigned int cpu) > > +{ > > + int i, level; > > + unsigned int freq = CPUFREQ_ENTRY_INVALID; > > + struct cpufreq_frequency_table *table = > > + cpufreq_frequency_get_table(cpu); > > + > > + if (!table) > > + return -EINVAL; > > + > > + for (i = 0, level = 0; table[i].frequency != CPUFREQ_TABLE_END; > > i++) { > > + /* Invalid entry */ > > + if (table[i].frequency == CPUFREQ_ENTRY_INVALID) > > + continue; > > + > > + /* Duplicate entry */ > > + if (freq == table[i].frequency) > > + continue; > > + > > + /* First valid entry */ > > + if (freq == CPUFREQ_ENTRY_INVALID) > > + freq = table[i].frequency; > > + > > + level++; > > + } > > + > > + return level; > > +} > > +EXPORT_SYMBOL(cpufreq_cooling_get_max_level); > > + > > +/** > > * get_cpu_frequency - get the absolute value of frequency from level. > > * @cpu: cpu for which frequency is fetched. > > * @level: level of frequency of the CPU
I have a question about this comment. it says that. * @level: level of frequency of the CPU * e.g level=1 --> 1st MAX FREQ, LEVEL=2 ---> 2nd MAX FREQ, ....etc" I think this is wrong because level equals cooling state, which starts from 0, rather than 1. IMO, it should be "level (cooling state) = 0 --> 1st MAX FREQ". what do you think? > > @@ -123,46 +157,58 @@ static int is_cpufreq_valid(int cpu) > > */ > > static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long > > level) > > { > > - int ret = 0, i = 0; > > - unsigned long level_index; > > + int i, count; > > + int max_level; > > + unsigned int freq = CPUFREQ_ENTRY_INVALID; > > bool descend = false; > > struct cpufreq_frequency_table *table = > > cpufreq_frequency_get_table(cpu); > > - if (!table) > > - return ret; > > > > - while (table[i].frequency != CPUFREQ_TABLE_END) { > > + max_level = cpufreq_cooling_get_max_level(cpu); > > + > > + if (max_level < 0) > > + return max_level; > > + > > + if (level > max_level) > > + return -EINVAL; > > + > > + for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) { > > if (table[i].frequency == CPUFREQ_ENTRY_INVALID) > > continue; > > > > - /*check if table in ascending or descending order*/ > > - if ((table[i + 1].frequency != CPUFREQ_TABLE_END) && > > - (table[i + 1].frequency < table[i].frequency) > > - && !descend) { > > - descend = true; > > + if (freq == CPUFREQ_ENTRY_INVALID) > > + /* first valid entry */ > > + freq = table[i].frequency; > > + else if (freq == table[i].frequency) > > + /* duplicate entry */ > > + continue; > > + else { > > + /* two valid entries, check frequency order */ > > + descend = !!(freq > table[i].frequency); > > + break; > > } > > - > > - /*return if level matched and table in descending order*/ > > - if (descend && i == level) > > - return table[i].frequency; > > - i++; > > } > > - i--; > > > > - if (level > i || descend) > > - return ret; > > - level_index = i - level; > > + /* level equals "the index of valid entries" in cpufreq table */ > > + level = descend ? level : max_level - level + 1; > > > > - /*Scan the table in reverse order and match the level*/ > > - while (i >= 0) { > > + freq = CPUFREQ_ENTRY_INVALID; > > + for (i = 0, count = 0; table[i].frequency != CPUFREQ_TABLE_END; > > i++) { > > + /* ignore invalid entry */ > > if (table[i].frequency == CPUFREQ_ENTRY_INVALID) > > continue; > > - /*return if level matched*/ > > - if (i == level_index) > > + > > + if (freq == CPUFREQ_ENTRY_INVALID) > > + /* first valid entry */ > > + freq = table[i].frequency; > > + else if (freq == table[i].frequency) > > + /* ignore duplicate entry */ > > + continue; > > + count++; > > + if (level == count) > > return table[i].frequency; > > - i--; > > } > > - return ret; > > + return -ENODEV; > > } > > > > /** > > @@ -244,29 +290,17 @@ static int cpufreq_get_max_state(struct > > thermal_cooling_device *cdev, > > struct cpufreq_cooling_device *cpufreq_device = cdev->devdata; > > struct cpumask *maskPtr = &cpufreq_device->allowed_cpus; > > unsigned int cpu; > > - struct cpufreq_frequency_table *table; > > - unsigned long count = 0; > > - int i = 0; > > + int max_level; > > > > cpu = cpumask_any(maskPtr); > > - table = cpufreq_frequency_get_table(cpu); > > - if (!table) { > > - *state = 0; > > - return 0; > > - } > > - > > - for (i = 0; (table[i].frequency != CPUFREQ_TABLE_END); i++) { > > - if (table[i].frequency == CPUFREQ_ENTRY_INVALID) > > - continue; > > - count++; > > - } > > > > - if (count > 0) { > > - *state = --count; > > - return 0; > > - } > > + max_level = cpufreq_cooling_get_max_level(cpu); > > > > - return -EINVAL; > > + if (max_level < 0) > > + return max_level; > > + else > > + *state = max_level; > > + return 0; > > } > > > > /** > > diff --git a/drivers/thermal/exynos_thermal.c > > b/drivers/thermal/exynos_thermal.c > > index cd71e24..5ac2de1 100644 > > --- a/drivers/thermal/exynos_thermal.c > > +++ b/drivers/thermal/exynos_thermal.c > > @@ -241,22 +241,7 @@ static int exynos_get_crit_temp(struct > > thermal_zone_device *thermal, > > > > static int exynos_get_frequency_level(unsigned int cpu, unsigned int freq) > > { > > - int i = 0, ret = -EINVAL; > > - struct cpufreq_frequency_table *table = NULL; > > -#ifdef CONFIG_CPU_FREQ > > - table = cpufreq_frequency_get_table(cpu); > > -#endif > > - if (!table) > > - return ret; > > - > > - while (table[i].frequency != CPUFREQ_TABLE_END) { > > - if (table[i].frequency == CPUFREQ_ENTRY_INVALID) > > - continue; > > - if (table[i].frequency == freq) > > - return i; > > - i++; > > - } > > - return ret; > > + return cpufreq_cooling_get_max_level(cpu); > This is not correct as it always gives the highest level. you are right. I'm proposing another patch. thanks, rui > > } > > > > /* Bind callback functions for thermal zone */ > > diff --git a/include/linux/cpu_cooling.h b/include/linux/cpu_cooling.h > > index 40b4ef5..2de9319 100644 > > --- a/include/linux/cpu_cooling.h > > +++ b/include/linux/cpu_cooling.h > > @@ -42,6 +42,14 @@ struct thermal_cooling_device *cpufreq_cooling_register( > > * @cdev: thermal cooling device pointer. > > */ > > void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev); > > + > > +/** > > + * cpufreq_cooling_get_max_level - function to get maxinum cooling state > > + * of a cpufreq cooling device > > + * @cpu: cpu of which frequency is fetched. > > + */ > > +int cpufreq_cooling_get_max_level(unsigned int cpu); > > + > > #else /* !CONFIG_CPU_THERMAL */ > > static inline struct thermal_cooling_device *cpufreq_cooling_register( > > const struct cpumask *clip_cpus) > > @@ -53,6 +61,10 @@ static inline void cpufreq_cooling_unregister( > > { > > return; > > } > > +static inline int cpufreq_cooling_get_max_level(unsigned int cpu) > > +{ > > + return -ENODEV; > > +} > > #endif /* CONFIG_CPU_THERMAL */ > > > > #endif /* __CPU_COOLING_H__ */ > > -- > > 1.7.9.5 > > > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majord...@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/