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tmk / tmk_keyboard

Keyboard firmwares for Atmel AVR and Cortex-M
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LUFA stack using 10-20% CPU in "System Interrupts" (windows) #223

Closed tocklime closed 9 years ago

tocklime commented 9 years ago

So I noticed in resmon.exe that "System Interrupts" or "Deferred Procedure Calls and Interrupt Service Routines" was taking 10-20% CPU nearly all the time.

Unplugging my ergodox (with TMK/LUFA stack) made the problem go away.

Out of interest, I recompiled the firmware with the PJRC stack, and the problem went away as well (although the PJRC stack has other issues).

I've made 2 traces I recorded using USBPcap - in both recordings I pressed the windows key a couple times then Ctrl-Ced the recording. You can see the LUFA one is constantly raising interrupts, but the PJRC one only raised a handful.

I don't know how to read USB/HID frames. Any idea what the LUFA firmware is trying to do? Or a better way of inspecting the traffic?

LUFA recording PJRC recording

Let me know if you'd rather I raised this on @cub-uanic 's ergodox branch, but he has said in another issue that he hasn't played with the USB stacks.

tmk commented 9 years ago

Most of that LUFA data is probably 'debug console data'(Endpoint 4 IN), uneeded empty data seems to be sent every 1ms. Console_Task of protocol/lufa/lufa.c may be a cause.

Build firmware with commenting out CONSOLE_ENABLE line of your Makefile to see the difference of CPU usage.

tocklime commented 9 years ago

Commenting out CONSOLE_ENABLE seems to produce a firmware which doesn't work at all (well, Magic-Space-B got me back to the bootloader, but it didn't work as a keyboard.)

tocklime commented 9 years ago

...actually, it works a bit more than that. Layer switching works, and my bootloader keystroke works, and power. But none of the normal keys seem to.

tmk commented 9 years ago

You are on Windows? If so remove device drivers of your keyboard from Device Manager. https://github.com/tmk/tmk_keyboard/wiki/FAQ-Build#2-remove-drivers-from-device-managerwindows

tocklime commented 9 years ago

Thanks. I'm now running LUFA without the cpu drain, but also without the console. I don't really need the console for day to day use (although I did have an idea to make a layer visualiser using a wrapped hid_listen.exe).

tmk commented 9 years ago

I'll look into Console_Task code later.

BTW, What's your OS actually? I don't see this problem on my Windows 7.

tocklime commented 9 years ago

Windows 8.1 Pro. I've got another win 8.1 pro machine at home. I'll try it on that later and see if I get the same behaviour.

tmk commented 9 years ago

Hopefully fixed at https://github.com/tmk/tmk_keyboard/commit/fdce0c9cc0b7f8e9f1497cae3ea63a6672ceaf71