output modules simplify locking for mixer reset and load

- fixes the deadlock in px4io ioctl mixer reset
   - px4io Run() locks (CDev semaphore)
   - mixer load goes through px4io ioctl MIXERIOCRESET which calls MixingOutput::resetMixerThreadSafe()
   - MixingOutput::resetMixerThreadSafe() stores a Command::Type::resetMixer command in an atomic variable, schedules a work queue cycle, then sleep spins until the command is cleared
   - the execution of the cycle eventually calls back into PX4IO::updateOutputs(), which tries to lock (and waits forever)
This commit is contained in:
Daniel Agar
2022-04-19 08:52:17 +02:00
committed by Beat Küng
parent 5d95cc001f
commit 5e05d98fe2
11 changed files with 72 additions and 172 deletions
+9 -7
View File
@@ -1,6 +1,6 @@
/****************************************************************************
*
* Copyright (c) 2021 PX4 Development Team. All rights reserved.
* Copyright (c) 2021-2022 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -36,6 +36,8 @@
#include <board_pwm_out.h>
#include <drivers/drv_hrt.h>
#include <px4_platform_common/sem.hpp>
using namespace pwm_out;
LinuxPWMOut::LinuxPWMOut() :
@@ -124,6 +126,8 @@ bool LinuxPWMOut::updateOutputs(bool stop_motors, uint16_t outputs[MAX_ACTUATORS
void LinuxPWMOut::Run()
{
SmartLock lock_guard(_lock);
if (should_exit()) {
ScheduleClear();
_mixing_output.unregister();
@@ -301,21 +305,21 @@ void LinuxPWMOut::update_params()
int LinuxPWMOut::ioctl(device::file_t *filp, int cmd, unsigned long arg)
{
SmartLock lock_guard(_lock);
int ret = OK;
PX4_DEBUG("ioctl cmd: %d, arg: %ld", cmd, arg);
lock();
switch (cmd) {
case MIXERIOCRESET:
_mixing_output.resetMixerThreadSafe();
_mixing_output.resetMixer();
break;
case MIXERIOCLOADBUF: {
const char *buf = (const char *)arg;
unsigned buflen = strlen(buf);
ret = _mixing_output.loadMixerThreadSafe(buf, buflen);
ret = _mixing_output.loadMixer(buf, buflen);
update_params();
break;
}
@@ -325,8 +329,6 @@ int LinuxPWMOut::ioctl(device::file_t *filp, int cmd, unsigned long arg)
break;
}
unlock();
if (ret == -ENOTTY) {
ret = CDev::ioctl(filp, cmd, arg);
}