1 /**
2 * Copyright 2017 Google Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 #include "config.h"
17
18 #include "fancontroller.hpp"
19
20 #include "tuning.hpp"
21 #include "util.hpp"
22 #include "zone.hpp"
23
24 #include <algorithm>
25 #include <cmath>
26 #include <iostream>
27
28 namespace pid_control
29 {
30
createFanPid(ZoneInterface * owner,const std::string & id,const std::vector<std::string> & inputs,const ec::pidinfo & initial)31 std::unique_ptr<PIDController> FanController::createFanPid(
32 ZoneInterface* owner, const std::string& id,
33 const std::vector<std::string>& inputs, const ec::pidinfo& initial)
34 {
35 if (inputs.size() == 0)
36 {
37 return nullptr;
38 }
39 auto fan = std::make_unique<FanController>(id, inputs, owner);
40 ec::pid_info_t* info = fan->getPIDInfo();
41
42 initializePIDStruct(info, initial);
43
44 return fan;
45 }
46
inputProc(void)47 double FanController::inputProc(void)
48 {
49 double value = 0.0;
50 std::vector<double> values;
51 std::vector<double>::iterator result;
52
53 try
54 {
55 for (const auto& name : _inputs)
56 {
57 // Read the unscaled value, to correctly recover the RPM
58 value = _owner->getCachedValues(name).unscaled;
59
60 /* If we have a fan we can't read, its value will be 0 for at least
61 * some boards, while others... the fan will drop off dbus (if
62 * that's how it's being read and in that case its value will never
63 * be updated anymore, which is relatively harmless, except, when
64 * something tries to read its value through IPMI, and can't, they
65 * sort of have to guess -- all the other fans are reporting, why
66 * not this one? Maybe it's unable to be read, so it's "bad."
67 */
68 if (!(std::isfinite(value)))
69 {
70 continue;
71 }
72 if (value <= 0.0)
73 {
74 continue;
75 }
76
77 values.push_back(value);
78 }
79 }
80 catch (const std::exception& e)
81 {
82 std::cerr << "exception on inputProc.\n";
83 throw;
84 }
85
86 /* Reset the value from the above loop. */
87 value = 0.0;
88 if (values.size() > 0)
89 {
90 /* the fan PID algorithm was unstable with average, and seemed to work
91 * better with minimum. I had considered making this choice a variable
92 * in the configuration, and it's a nice-to-have..
93 */
94 result = std::min_element(values.begin(), values.end());
95 value = *result;
96 }
97
98 return value;
99 }
100
setptProc(void)101 double FanController::setptProc(void)
102 {
103 double maxRPM = _owner->getMaxSetPointRequest();
104
105 // store for reference, and check if more or less.
106 double prev = getSetpoint();
107
108 if (maxRPM > prev)
109 {
110 setFanDirection(FanSpeedDirection::UP);
111 }
112 else if (prev > maxRPM)
113 {
114 setFanDirection(FanSpeedDirection::DOWN);
115 }
116 else
117 {
118 setFanDirection(FanSpeedDirection::NEUTRAL);
119 }
120
121 setSetpoint(maxRPM);
122
123 return (maxRPM);
124 }
125
outputProc(double value)126 void FanController::outputProc(double value)
127 {
128 double percent = value;
129
130 /* If doing tuning, don't go into failsafe mode. */
131 if (!tuningEnabled)
132 {
133 bool failsafeCurrState = _owner->getFailSafeMode();
134
135 // Note when failsafe state transitions happen
136 if (failsafePrevState != failsafeCurrState)
137 {
138 failsafePrevState = failsafeCurrState;
139 failsafeTransition = true;
140 }
141
142 if (failsafeCurrState)
143 {
144 double failsafePercent = _owner->getFailSafePercent();
145
146 #ifdef STRICT_FAILSAFE_PWM
147 // Unconditionally replace the computed PWM with the
148 // failsafe PWM if STRICT_FAILSAFE_PWM is defined.
149 percent = failsafePercent;
150 #else
151 // Ensure PWM is never lower than the failsafe PWM.
152 // The computed PWM is still allowed to rise higher than
153 // failsafe PWM if STRICT_FAILSAFE_PWM is NOT defined.
154 // This is the default behavior.
155 if (percent < failsafePercent)
156 {
157 percent = failsafePercent;
158 }
159 #endif
160 }
161
162 // Always print if debug enabled
163 if (debugEnabled)
164 {
165 std::cerr << "Zone " << _owner->getZoneID() << " fans, "
166 << (failsafeCurrState ? "failsafe" : "normal")
167 << " mode, output pwm: " << percent << "\n";
168 }
169 else
170 {
171 // Only print once per transition when not debugging
172 if (failsafeTransition)
173 {
174 failsafeTransition = false;
175 std::cerr << "Zone " << _owner->getZoneID() << " fans, "
176 << (failsafeCurrState ? "entering failsafe"
177 : "returning to normal")
178 << " mode, output pwm: " << percent << "\n";
179 }
180 }
181 }
182 else
183 {
184 if (debugEnabled)
185 {
186 std::cerr << "Zone " << _owner->getZoneID()
187 << " fans, tuning mode, bypassing failsafe, output pwm: "
188 << percent << "\n";
189 }
190 }
191
192 // value and kFanFailSafeDutyCycle are 10 for 10% so let's fix that.
193 percent /= 100.0;
194
195 // PidSensorMap for writing.
196 for (const auto& it : _inputs)
197 {
198 auto sensor = _owner->getSensor(it);
199 auto redundantWrite = _owner->getRedundantWrite();
200 int64_t rawWritten = -1;
201 sensor->write(percent, redundantWrite, &rawWritten);
202
203 // The outputCache will be used later,
204 // to store a record of the PWM commanded,
205 // so that this information can be included during logging.
206 auto unscaledWritten = static_cast<double>(rawWritten);
207 _owner->setOutputCache(sensor->getName(), {percent, unscaledWritten});
208 }
209
210 return;
211 }
212
~FanController()213 FanController::~FanController()
214 {
215 #ifdef OFFLINE_FAILSAFE_PWM
216 double percent = _owner->getFailSafePercent();
217 if (debugEnabled)
218 {
219 std::cerr << "Zone " << _owner->getZoneID()
220 << " offline fans output pwm: " << percent << "\n";
221 }
222
223 // value and kFanFailSafeDutyCycle are 10 for 10% so let's fix that.
224 percent /= 100.0;
225
226 // PidSensorMap for writing.
227 for (const auto& it : _inputs)
228 {
229 auto sensor = _owner->getSensor(it);
230 auto redundantWrite = _owner->getRedundantWrite();
231 int64_t rawWritten;
232 sensor->write(percent, redundantWrite, &rawWritten);
233
234 // The outputCache will be used later,
235 // to store a record of the PWM commanded,
236 // so that this information can be included during logging.
237 auto unscaledWritten = static_cast<double>(rawWritten);
238 _owner->setOutputCache(sensor->getName(), {percent, unscaledWritten});
239 }
240 #endif
241 }
242
243 } // namespace pid_control
244