On Saturday 13 February 2021 10:30:19 nnet wrote:
> On Sat, Feb 13, 2021, at 2:01 AM, Pali Rohár wrote:
> > On Thursday 11 February 2021 16:41:13 nnet wrote:
> > > On Thu, Feb 11, 2021, at 3:44 PM, Pali Rohár wrote:
> > > > On Thursday 11 February 2021 12:22:52 nnet wrote:
> > > > > On Thu, Feb 11, 2021, at 11:55 AM, Pali Rohár wrote:
> > > > > > On Wednesday 10 February 2021 11:08:59 nnet wrote:
> > > > > > > On Wed, Feb 10, 2021, at 10:03 AM, Pali Rohár wrote:
> > > > > > > > > > Hello! Could you please enable userspace governor during
> > > > > > > > > > kernel
> > > > > > > > > > compilation?
> > > > > > > > > >
> > > > > > > > > > CONFIG_CPU_FREQ_GOV_USERSPACE=y
> > > > > > > > > >
> > > > > > > > > > It can be activated via command:
> > > > > > > > > >
> > > > > > > > > > echo userspace >
> > > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > > > > > > > >
> > > > > > > > > > After that you can "force" CPU frequency to specific value,
> > > > > > > > > > e.g.:
> > > > > > > > > >
> > > > > > > > > > echo 1000000 >
> > > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed
> > > > > > > > > >
> > > > > > > > > > I need to know which switch (from --> to freq) cause this
> > > > > > > > > > system hang.
> > > > > > > > > >
> > > > > > > > > > This patch series (via MIN_VOLT_MV_FOR_L0_L1_1GHZ) is
> > > > > > > > > > fixing only
> > > > > > > > > > switching from 500 MHz to 1000 MHz on 1 GHz variant. As
> > > > > > > > > > only this switch
> > > > > > > > > > is causing issue.
> > > > > > > > > >
> > > > > > > > > > I have used following simple bash script to check that
> > > > > > > > > > switching between
> > > > > > > > > > 500 MHz and 1 GHz is stable:
> > > > > > > > > >
> > > > > > > > > > while true; do
> > > > > > > > > > echo 1000000 >
> > > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > > > > > echo 500000 >
> > > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > > > > > echo 1000000 >
> > > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > > > > > echo 500000 >
> > > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > > > > > done
> > > > > > > > >
> > > > > > > > > echo userspace | tee
> > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > > > > > > > while true; do
> > > > > > > > > echo 1200000 | tee
> > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > > > > echo 600000 | tee
> > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > > > > done
> > > > > > > > >
> > > > > > > > > >> +#define MIN_VOLT_MV_FOR_L0_L1_1GHZ 1108
> > > > > > > > >
> > > > > > > > > With 1108 I get a freeze within a minute. The last output to
> > > > > > > > > stdout is 600000.
> > > > > > > > >
> > > > > > > > > With 1120 it takes a few minutes.
> > > > > > > > >
> > > > > > > > > With any of 1225, 1155, 1132 the device doesn't freeze over
> > > > > > > > > the full 5 minute load test.
> > > > > > > > >
> > > > > > > > > I'm using ondemand now with the above at 1132 without issue
> > > > > > > > > so far.
> > > > > > > >
> > > > > > > > Great, thank you for testing!
> > > > > > > >
> > > > > > > > Can you check if switching between any two lower frequencies
> > > > > > > > 200000
> > > > > > > > 300000 600000 is stable?
> > > > > > >
> > > > > > > This is stable using 1132 mV for MIN_VOLT_MV_FOR_L0_L1_1GHZ:
> > > > > > >
> > > > > > > while true; do
> > > > > > > # down
> > > > > > > echo 1200000 | tee
> > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > ...
> > > > > >
> > > > > > Hello!
> > > > > >
> > > > > > Could you please re-run test without tee, in form as I have shown
> > > > > > above?
> > > > > > UART is slow and printing something to console adds delay which
> > > > > > decrease
> > > > > > probability that real issue is triggered as this is timing issue.
> > > > >
> > > > > The test was done over SSH.
> > > >
> > > > Ok! But it is still better to not print any results as it adds unwanted
> > > > delay between frequency switching.
> > > >
> > > > > > Also please do tests just between two frequencies in loop as I
> > > > > > observed
> > > > > > that switching between more decreased probability to hit issue.
> > > > >
> > > > > > > > > echo userspace | tee
> > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > > > > > > > while true; do
> > > > > > > > > echo 1200000 | tee
> > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > > > > echo 600000 | tee
> > > > > > > > > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > > > > > > > done
> > > > >
> > > > > The first test ^ switched between 600 MHz and 1.2 GHz.
> > > > >
> > > > > > The real issue for 1 GHz variant of A3720 is only when doing switch
> > > > > > from
> > > > > > 500 MHz to 1 GHz. So could you try to do some tests also without
> > > > > > changing MIN_VOLT_MV_FOR_L0_L1_1GHZ and switching just between
> > > > > > non-1.2
> > > > > > frequencies (to verify that on 1.2 GHz variant it is also from 600
> > > > > > MHz
> > > > > > to 1.2 GHz)?
> > > > >
> > > > > With 1108 mV and switching between 600 MHz and 1.2GHz, I always saw a
> > > > > freeze within a minute.
> > > >
> > > > I mean to try switching with 1.108 V between 200 MHz and 300 MHz or
> > > > between 300 MHz and 600 MHz. To check that issue is really only with
> > > > switch from 600 MHz to 1.2 GHz.
> > >
> > > With:
> > >
> > > +#define MIN_VOLT_MV_FOR_L0_L1_1GHZ 1108
> > >
> > > with 5 min load:
> > >
> > > # no lock-up
> > >
> > > echo userspace > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > while true; do
> > > echo 200000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > echo 300000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > done
> > >
> > > # no lock-up
> > >
> > > echo userspace > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > while true; do
> > > echo 300000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > echo 600000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > done
> > >
> > > # lock-up with 10 seconds of load applied
> > >
> > > echo userspace > /sys/devices/system/cpu/cpufreq/policy0/scaling_governor
> > > while true; do
> > > echo 600000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > echo 1200000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed;
> > > done
> >
> > Ok! So it really looks like that on 1.2 GHz is the same issue. We need
> > to increase voltage for L1 load (600 MHz). But question is what is the
> > threshold (it is 1132 mV or lower?)
>
> Lower then 1132 mV causes freezes. No freezes with 1132 mV.
>
> > and second question is what
> > increasing minimal voltage may cause with board.
>
> I don't have any further information on the issue and device then that
> experience.
>
> I've tested on two of these devices which suggests it's not an oddity with
> one instance of it.
Ok, thank you for information.
Could you test following change instead of PATCH 04/10? I added here also
logic for 1.2 GHz variant with 1.132 V value and another change is that
value for load L0 is not touched as it is stable.
diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c
b/drivers/cpufreq/armada-37xx-cpufreq.c
index b8dc6c849..8a4afb048 100644
--- a/drivers/cpufreq/armada-37xx-cpufreq.c
+++ b/drivers/cpufreq/armada-37xx-cpufreq.c
@@ -73,6 +73,8 @@
#define LOAD_LEVEL_NR 4
#define MIN_VOLT_MV 1000
+#define MIN_VOLT_MV_FOR_L1_1000MHZ 1108
+#define MIN_VOLT_MV_FOR_L1_1200MHZ 1132
/* AVS value for the corresponding voltage (in mV) */
static int avs_map[] = {
@@ -208,6 +210,8 @@ static u32 armada_37xx_avs_val_match(int target_vm)
* - L2 & L3 voltage should be about 150mv smaller than L0 voltage.
* This function calculates L1 & L2 & L3 AVS values dynamically based
* on L0 voltage and fill all AVS values to the AVS value table.
+ * When base CPU frequency is 1000 or 1200 MHz then there is additional
+ * minimal avs value for load L1.
*/
static void __init armada37xx_cpufreq_avs_configure(struct regmap *base,
struct armada_37xx_dvfs *dvfs)
@@ -239,6 +243,18 @@ static void __init armada37xx_cpufreq_avs_configure(struct
regmap *base,
for (load_level = 1; load_level < LOAD_LEVEL_NR; load_level++)
dvfs->avs[load_level] = avs_min;
+ /*
+ * Set the avs value for load L0 and L1 when base CPU frequency
is 1000/1200 MHz,
+ * otherwise the CPU gets stuck when switching from load L1 to
load L0.
+ */
+ if (dvfs->cpu_freq_max >= 1000*1000*1000) {
+ if (dvfs->cpu_freq_max >= 1200*1000*1000)
+ avs_min =
armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1200MHZ);
+ else
+ avs_min =
armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1000MHZ);
+ dvfs->avs[0] = dvfs->avs[1] = avs_min;
+ }
+
return;
}
@@ -258,6 +274,26 @@ static void __init armada37xx_cpufreq_avs_configure(struct
regmap *base,
target_vm = avs_map[l0_vdd_min] - 150;
target_vm = target_vm > MIN_VOLT_MV ? target_vm : MIN_VOLT_MV;
dvfs->avs[2] = dvfs->avs[3] = armada_37xx_avs_val_match(target_vm);
+
+ /*
+ * Fix the avs value for load L1 when base CPU frequency is 1000/1200
MHz,
+ * otherwise the CPU gets stuck when switching from load L1 to load L0.
+ * Also ensure that avs value for load L1 is not higher than for L0.
+ */
+ if (dvfs->cpu_freq_max >= 1000*1000*1000) {
+ u32 avs_min_l1;
+
+ if (dvfs->cpu_freq_max >= 1200*1000*1000)
+ avs_min_l1 =
armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1200MHZ);
+ else
+ avs_min_l1 =
armada_37xx_avs_val_match(MIN_VOLT_MV_FOR_L1_1000MHZ);
+
+ if (avs_min_l1 > dvfs->avs[0])
+ avs_min_l1 = dvfs->avs[0];
+
+ if (dvfs->avs[1] < avs_min_l1)
+ dvfs->avs[1] = avs_min_l1;
+ }
}
static void __init armada37xx_cpufreq_avs_setup(struct regmap *base,
> >
> > Basically there is absolutely no information about 1.2 GHz variant and
> > this issue...
> >
> > > > I need to know if current settings are fine for 200, 300 and 600 MHz
> > > > frequencies and the only 600 --> 1200 needs to be fixed.
> > > >
> >
