@@ -283,11 +283,11 @@ int update_devfreq(struct devfreq *devfreq)
max_freq = MIN(devfreq->scaling_max_freq, devfreq->max_freq);
min_freq = MAX(devfreq->scaling_min_freq, devfreq->min_freq);
- if (min_freq && freq < min_freq) {
+ if (freq < min_freq) {
freq = min_freq;
flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
}
- if (max_freq && freq > max_freq) {
+ if (freq > max_freq) {
freq = max_freq;
flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
}
@@ -1126,17 +1126,26 @@ static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
struct devfreq *df = to_devfreq(dev);
unsigned long value;
int ret;
- unsigned long max;
ret = sscanf(buf, "%lu", &value);
if (ret != 1)
return -EINVAL;
mutex_lock(&df->lock);
- max = df->max_freq;
- if (value && max && value > max) {
- ret = -EINVAL;
- goto unlock;
+
+ if (value) {
+ if (value > df->max_freq) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ } else {
+ unsigned long *freq_table = df->profile->freq_table;
+
+ /* Get minimum frequency according to sorting order */
+ if (freq_table[0] < freq_table[df->profile->max_state - 1])
+ value = freq_table[0];
+ else
+ value = freq_table[df->profile->max_state - 1];
}
df->min_freq = value;
@@ -1161,17 +1170,26 @@ static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
struct devfreq *df = to_devfreq(dev);
unsigned long value;
int ret;
- unsigned long min;
ret = sscanf(buf, "%lu", &value);
if (ret != 1)
return -EINVAL;
mutex_lock(&df->lock);
- min = df->min_freq;
- if (value && min && value < min) {
- ret = -EINVAL;
- goto unlock;
+
+ if (value) {
+ if (value < df->min_freq) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ } else {
+ unsigned long *freq_table = df->profile->freq_table;
+
+ /* Get maximum frequency according to sorting order */
+ if (freq_table[0] < freq_table[df->profile->max_state - 1])
+ value = freq_table[df->profile->max_state - 1];
+ else
+ value = freq_table[0];
}
df->max_freq = value;
Commit ab8f58ad72c4 ("PM / devfreq: Set min/max_freq when adding the devfreq device") initializes df->min/max_freq with the min/max OPP when the device is added. Later commit f1d981eaecf8 ("PM / devfreq: Use the available min/max frequency") adds df->scaling_min/max_freq and the following to the frequency adjustment code: max_freq = MIN(devfreq->scaling_max_freq, devfreq->max_freq); With the current handling of min/max_freq this is incorrect: Even though df->max_freq is now initialized to a value != 0 user space can still set it to 0, in this case max_freq would be 0 instead of df->scaling_max_freq as intended. In consequence the frequency adjustment is not performed: if (max_freq && freq > max_freq) { freq = max_freq; To fix this set df->min/max freq to the min/max OPP in max/max_freq_store, when the user passes a value of 0. This also prevents df->max_freq from being set below the min OPP when df->min_freq is 0, and similar for min_freq. Since it is now guaranteed that df->min/max_freq can't be 0 the checks for this case can be removed. Fixes: f1d981eaecf8 ("PM / devfreq: Use the available min/max frequency") Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Brian Norris <briannorris@chromium.org> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com> --- Changes in v6: - min/max_freq_store(): updated comment about sorting order of frequency table - min/max_freq_store(): moved declaration of 'freq_table' into the block that uses it - added 'Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>' tag Changes in v5: - none Changes in v4: - added 'Reviewed-by: Brian Norris <briannorris@chromium.org>' tag Changes in v3: - none Changes in v2: - handle freq tables sorted in ascending and descending order in min/max_freq_store() - use same order for conditional statements in min/max_freq_store() --- drivers/devfreq/devfreq.c | 42 ++++++++++++++++++++++++++++----------- 1 file changed, 30 insertions(+), 12 deletions(-)