[Letux-kernel] [PATCH 00/20] A bunch of JZ4730 fixups for letux-kernel

[H. Nikolaus Schaller]

> Am 29.12.2020 um 17:41 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> 
>> Am 29.12.2020 um 17:23 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
>> 
>>> Debian GNU/Linux 8 letux console
>>> 
>>> letux login: [   80.122152] sched_clock_poll wrap_kt=568880208
>>> [   80.620659] sched_clock_poll wrap_kt=568880208
>>> [   81.112222] sched_clock_poll wrap_kt=568880208
>>> [   81.604565] sched_clock_poll wrap_kt=568880208
>>> [   82.091423] sched_clock_poll wrap_kt=568880208
>>> [   82.587465] sched_clock_poll wrap_kt=568880208
>>> [   83.075520] sched_clock_poll wrap_kt=568880208
>>> 
>>> If I read the wrap_kt as ns it means the hrtimer is triggered every 0.5 seconds.
>>> This translates in 0.5 seconds increments of the sched_clock() for the
>>> printk statements. Fine.
>>> 
>>> But it is far to slow compared to your estimate of ca. 25 wraps per second.
> 
> Just noticed. Yes, the hrtimer is triggered every 0.5 seconds,
> but kernel time and not real time.
> 
> So I think some clocks are running at the wrong (too slow) speed.
> 
> I think we should find a way to read out all the clock frequencies
> as seen by the kernel...

Ok, found it:

root at letux:~# (cd /sys/kernel/debug/clk/; for i in *; do echo $i: $(cat "$i/clk_rate"); done) 2>/dev/null
ak4643_mcko: 12000000
cclk: 335462400
cclkdiv: 335462400
clk-usb: 47923200
clk_dump:
clk_orphan_dump:
clk_orphan_summary:
clk_summary:
dma: 111820800
ext: 3686400
ext_div128: 4294967295
hclk: 111820800
hclkdiv: 111820800
i2c: 111820800
i2s: 335462400
lcd: 111820800
lcd_pclk: 335462400
lcddiv: 111820800
mclk: 111820800
mclkdiv: 111820800
mmc: 24000000
msc16m: 16000000
msc24m: 24000000
pcf8563-clkout: 32768
pclk: 111820800
pclkdiv: 111820800
pll: 335462400
pll half: 4294967295
rtc: 32768
spi: 335462400
tcu: 3686400
timer0: 57600
timer1: 57600
timer2: 57600
uart0: 3686400
uart1: 3686400
uart2: 3686400
uart3: 3686400
uhc: 47923200
uhcdiv: 47923200
usb48m: 48000000
wdt: 4294967295
root at letux:~# 

This does not mean that a clock really has this frequency.

BTW: I have played a little with the gpio mouse buttons. The
interrupts are not enabled. And they appear to be active high.
Will also investigate...

BR,
Nikolaus