Adafruit_BBIO PWM does not work Linux 4.9 kernel

[pdp7]

Issue

Adafruit_BBIO PWM does not work Linux 4.9 kernel.

I will update with more information about the issue and my progress as I work towards resolution. I wanted to quickly log an issue so that the problem is visible to everyone.

Workaround

Use the Linux 4.4 kernel

cd /opt/scripts/tools/
sudo git pull
sudo ./update_kernel.sh --lts-4_4
sudo reboot

[silver2row]

Hello Sir,

Thank you for adopting this issue. I will stay patient.

Seth

[pdp7]

@silver2row please try switching to the Linux 4.4 kernel. The issue with the Flask demo described in #168 may be unrelated but I'd like to eliminate this Linux 4.9 kernel issue from your situation.

[silver2row]

Hello Sir,

Seth here. I tried to run that software on kernel 4.4.x and I received all sorts of issues.

Seth

P.S. I am currently dealing with the Flask people on GitHub.com.

[silver2row]

Hello,

I set up a question on Stack Overflow: https://stackoverflow.com/questions/46654985/re-how-can-i-get-flask-to-use-gpio-pins-to-change-the-led-brightness-on-linux-w.

Seth

P.S. If you are interested in looking at what has happened so far, go ahead. The link is listed above.

[pdp7]

@silver2row

Seth here. I tried to run that software on kernel 4.4.x and I received all sorts of issues.

Please paste the any errors or warning here so that I can them.

[silver2row]

Hello...power constraints @pdp7 .

Sorry. I feel bad now. I was trying to power everything, one sensor and an LED, with the 3.3v. I think your Adafruit_BBIO works and actually, I know it does.

I am foolish at times and forgot about power issues.

Seth

P.S. I am very sorry. Please forgive me.

[pdp7]

@silver2row Thank you for making me take a closer look at PWM. There is a real bug with PWM in Adafruit_BBIO on Linux 4.9 kernel. I am able to reproduce it and will post more details here soon.

[pdp7]

Workaround by @RobertCNelson in c35e4cb

Merged in #173

[pdp7]

@RobertCNelson pytest looking pretty good on the new BeagleBoard.org Debian Image 2017-10-17 image

pytest

note: install pytest with sudo pip install pytest

debian@beaglebone:/opt/source/adafruit-beaglebone-io-python$ sudo pytest test/*
====================================================== test session starts =======================================================
platform linux2 -- Python 2.7.13, pytest-3.2.3, py-1.4.34, pluggy-0.4.0
rootdir: /opt/source/adafruit-beaglebone-io-python, inifile:
collected 58 items                                                                                                                

test/test_adc.py ......
test/test_gpio_input.py ..
test/test_gpio_output.py ......
test/test_gpio_setup.py ..........
test/test_led.py ..
test/test_pwm_setup.py ..F........................
test/test_spi.py ..
test/test_uart.py ...

============================================================ FAILURES ============================================================
_________________________________________ TestPwmSetup.test_start_pwm_with_polarity_one __________________________________________

self = <test_pwm_setup.TestPwmSetup instance at 0xb640da08>

    def test_start_pwm_with_polarity_one(self):
        PWM.cleanup()
        PWM.start("P9_14", 0, 2000, 1)
    
        pwm_dir = get_pwm_dir()
    
        assert os.path.exists(pwm_dir)
        if kernel >= '4.1.0':
            duty = open(pwm_dir + '/duty_cycle').read()
        else:
            duty = open(pwm_dir + '/duty').read()
        period = open(pwm_dir + '/period').read()
        polarity = open(pwm_dir + '/polarity').read()
        assert int(duty) == 0
        assert int(period) == 500000
    
        if kernel >= '4.1.0':
>           assert polarity == "inversed\n"
E           AssertionError: assert 'normal\n' == 'inversed\n'
E             - normal
E             + inversed

test/test_pwm_setup.py:100: AssertionError
============================================== 1 failed, 57 passed in 12.84 seconds ==============================================

version.sh

debian@beaglebone:/opt/source/adafruit-beaglebone-io-python$ sudo /opt/scripts/tools/version.sh 
git:/opt/scripts/:[6c2688b0be448b7bb9ca18849b430d496a84acb4]
eeprom:[A335BNLT000C3014BBBK1316]
model:[TI_AM335x_BeagleBone_Black]
dogtag:[BeagleBoard.org Debian Image 2017-10-17]
bootloader:[microSD-(push-button)]:[/dev/mmcblk0]:[U-Boot 2017.09-00002-g0f3f1c7907]
bootloader:[eMMC-(default)]:[/dev/mmcblk1]:[U-Boot 2017.09-rc2-00002-g84a7f2]
kernel:[4.4.91-ti-r133]
nodejs:[v6.11.4]
uboot_overlay_options:[enable_uboot_overlays=1]
uboot_overlay_options:[uboot_overlay_pru=/lib/firmware/AM335X-PRU-RPROC-4-4-TI-00A0.dtbo]
uboot_overlay_options:[enable_uboot_cape_universal=1]
pkg:[bb-cape-overlays]:[4.4.20171013.2-0rcnee1~stretch+20171013]
pkg:[bb-wl18xx-firmware]:[1.20170829-0rcnee1~stretch+20170829]
pkg:[firmware-ti-connectivity]:[20170823-1rcnee0~stretch+20170830]