New subject: Device power saving feature - power measurements

26 May 2016

Hi folks.
This patch introduces a feature which allows an idle device (a device
which is not currently recording or streaming) to enter a power-down
mode after some period of time. Given two timeout values,
PowerdownTimeoutM and PowerdownWakeupH, it works like this: when a
device becomes idle, it is kept powered up for PowerdownTimeoutM minutes
doing, for instance, an EPG scan before it is powered down. If the
device is still idle and has been powered down for PowerdownWakeupH
hours it is powered up for PowerdownTimeoutM minutes and so on. When
recording, streaming or a forced EPG scan starts, the device is powered
up and it's idle timer is disabled. This implies that PowerdownTimeoutM
should be enough for a full round of EPG scanning (20 seconds *
number_of_transponders). Another option is to run EPG scans from cron
(at night) and use SVDRP SCAN command.
Actual implementation of power saving facilities is left to a derived
device class. In the case of a DVB device it is implemented by closing
it's frontend device. For a DVB-S/S2 tuner this usually means powering
the LNB off. My measurements show 3-4W power consumption drops per tuner
for various DVB-S/S2 tuners. So, this feature (together with HDD
spin-down) is especially valuable while running a headless 24/7 VDR
server and/or using several tuners. A SATIP device can also implement
power saving if it is supported by a server.
I know about the dynamite plugin, but 1) it does much more then this, 2)
still requires a VDR patch, which is bigger, 3) doesn't work reliably
for me and 4) I think this functionality should be part of the VDR
core.
A copy of the patch is here:
http://pastebin.com/FRi0kTjf
Please review,
Sergey Chernyavskiy.
---
 config.c    |  9 ++++++
 config.h    |  3 ++
 device.c    | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 device.h    | 29 +++++++++++++++++++
 dvbdevice.c | 39 +++++++++++++++++++++++++
 dvbdevice.h |  7 +++++
 eitscan.c   |  7 ++++-
 menu.c      |  9 +++++-
 vdr.c       |  6 ++++
 9 files changed, 201 insertions(+), 4 deletions(-)

diff --git a/config.c b/config.c
index e5f5463..794c9f8 100644
--- a/config.c
+++ b/config.c
@@ -395,6 +395,9 @@ cSetup::cSetup(void)
   PositionerSpeed = 15;
   PositionerSwing = 650;
   PositionerLastLon = 0;
+  PowerdownEnabled = 0;
+  PowerdownTimeoutM = 15;
+  PowerdownWakeupH = 4;
   SetSystemTime = 0;
   TimeSource = 0;
   TimeTransponder = 0;
@@ -622,6 +625,9 @@ bool cSetup::Parse(const char *Name, const char *Value)
   else if (!strcasecmp(Name, "PositionerSpeed"))     PositionerSpeed
  = atoi(Value);
   else if (!strcasecmp(Name, "PositionerSwing"))     PositionerSwing
  = atoi(Value);
   else if (!strcasecmp(Name, "PositionerLastLon"))
PositionerLastLon  = atoi(Value);
+  else if (!strcasecmp(Name, "PowerdownEnabled"))    PowerdownEnabled
  = atoi(Value);
+  else if (!strcasecmp(Name, "PowerdownTimeoutM"))
PowerdownTimeoutM  = atoi(Value);
+  else if (!strcasecmp(Name, "PowerdownWakeupH"))    PowerdownWakeupH
  = atoi(Value);
   else if (!strcasecmp(Name, "SetSystemTime"))       SetSystemTime
  = atoi(Value);
   else if (!strcasecmp(Name, "TimeSource"))          TimeSource
  = cSource::FromString(Value);
   else if (!strcasecmp(Name, "TimeTransponder"))     TimeTransponder
  = atoi(Value);
@@ -753,6 +759,9 @@ bool cSetup::Save(void)
   Store("PositionerSpeed",    PositionerSpeed);
   Store("PositionerSwing",    PositionerSwing);
   Store("PositionerLastLon",  PositionerLastLon);
+  Store("PowerdownEnabled",   PowerdownEnabled);
+  Store("PowerdownTimeoutM",  PowerdownTimeoutM);
+  Store("PowerdownWakeupH",   PowerdownWakeupH);
   Store("SetSystemTime",      SetSystemTime);
   Store("TimeSource",         cSource::ToString(TimeSource));
   Store("TimeTransponder",    TimeTransponder);
diff --git a/config.h b/config.h
index e5565da..7a73d9d 100644
--- a/config.h
+++ b/config.h
@@ -273,6 +273,9 @@ public:
   int PositionerSpeed;
   int PositionerSwing;
   int PositionerLastLon;
+  int PowerdownEnabled;
+  int PowerdownTimeoutM;
+  int PowerdownWakeupH;
   int SetSystemTime;
   int TimeSource;
   int TimeTransponder;
diff --git a/device.c b/device.c
index 542d120..9306adb 100644
--- a/device.c
+++ b/device.c
@@ -104,6 +104,9 @@ cDevice::cDevice(void)
   dvbSubtitleConverter = NULL;
   autoSelectPreferredSubtitleLanguage = true;
+  idleTimerExpires = time(NULL) + Setup.PowerdownTimeoutM * 60;
+  wakeupTimerExpires = 0;
+
   for (int i = 0; i < MAXRECEIVERS; i++)
       receiver[i] = NULL;
@@ -745,6 +748,11 @@ bool cDevice::SwitchChannel(int Direction)
   return result;
 }
+// While switching to a channel, the device will be kept powered up
+// for at least this number of seconds before a receiver is attached.
+// Must be less than cEITScanner::ScanTimeout.
+#define CHANNEL_SWITCH_POWERUP_TIMEOUT  10
+
 eSetChannelResult cDevice::SetChannel(const cChannel *Channel, bool LiveView)
 {
   cStatus::MsgChannelSwitch(this, 0, LiveView);
@@ -778,6 +786,8 @@ eSetChannelResult cDevice::SetChannel(const
cChannel *Channel, bool LiveView)
         Result = scrNotAvailable;
      }
   else {
+     // Power up the device
+     PowerUp(CHANNEL_SWITCH_POWERUP_TIMEOUT);
      // Stop section handling:
      if (sectionHandler) {
         sectionHandler->SetStatus(false);
@@ -843,8 +853,11 @@ int cDevice::Occupied(void) const
void cDevice::SetOccupied(int Seconds)
 {
-  if (Seconds >= 0)
+  if (Seconds >= 0) {
      occupiedTimeout = time(NULL) + min(Seconds, MAXOCCUPIEDTIMEOUT);
+     // avoid short power-down/power-up cycles
+     SetIdleTimer(true, Seconds + 30);
+     }
 }
bool cDevice::SetChannelDevice(const cChannel *Channel, bool LiveView)
@@ -1675,6 +1688,7 @@ bool cDevice::AttachReceiver(cReceiver *Receiver)
             startScrambleDetection = time(NULL);
             }
          Start();
+         SetIdleTimer(false);
          return true;
          }
       }
@@ -1708,8 +1722,10 @@ void cDevice::Detach(cReceiver *Receiver)
            camSlot->Assign(NULL);
         }
      }
-  if (!receiversLeft)
+  if (!receiversLeft) {
      Cancel(-1);
+     SetIdleTimer(true);
+     }
 }
void cDevice::DetachAll(int Pid)
@@ -1731,6 +1747,82 @@ void cDevice::DetachAllReceivers(void)
       Detach(receiver[i]);
 }
+void cDevice::CheckIdle(void)
+{
+  if (!SupportsPowerDown() || !Setup.PowerdownEnabled)
+     return;
+  cMutexLock MutexLock(&mutexPowerSaving);
+  if (idleTimerExpires != 0 && time(NULL) > idleTimerExpires) {
+     // idle, powered up
+     dsyslog("power saving: device %d idle timer expired", CardIndex() + 1);
+     SetIdleTimer(false);
+     if (Setup.PowerdownWakeupH != 0)
+        wakeupTimerExpires = time(NULL) + Setup.PowerdownWakeupH * 3600;
+     else
+        dsyslog("power saving: waking up is disabled");
+     if (!IsPoweredDown()) {
+        dsyslog("power saving: powering device %d down", CardIndex() + 1);
+        if (sectionHandler) {
+           sectionHandler->SetStatus(false);
+           sectionHandler->SetChannel(NULL);
+           }
+        PowerDown(true);
+        }
+     }
+  if (wakeupTimerExpires != 0 && time(NULL) > wakeupTimerExpires) {
+     // idle, powered down
+     dsyslog("power saving: device %d wakeup timer expired", CardIndex() + 1);
+     SetIdleTimer(true);
+     if (IsPoweredDown()) {
+        dsyslog("power saving: waking up device %d", CardIndex() + 1);
+        PowerDown(false);
+        }
+     }
+}
+
+void cDevice::SetIdleTimer(bool On, int ExtraTimeoutS)
+{
+  if (!SupportsPowerDown())
+     return;
+  cMutexLock MutexLock(&mutexPowerSaving);
+  if (On) {
+     int Tout = Setup.PowerdownTimeoutM * 60;
+     time_t Now = time(NULL);
+     if (ExtraTimeoutS > 0) {
+        if (idleTimerExpires >= Now + ExtraTimeoutS)
+           return;
+        Tout = ExtraTimeoutS;
+        }
+     idleTimerExpires = Now + Tout;
+     if (Setup.PowerdownEnabled)
+        dsyslog("power saving: set device %d idle timer to %d sec",
CardIndex() + 1, Tout);
+     }
+  else {
+     idleTimerExpires = 0;
+     if (Setup.PowerdownEnabled)
+        dsyslog("power saving: disable device %d idle timer", CardIndex() + 1);
+     }
+  wakeupTimerExpires = 0;
+}
+
+bool cDevice::PoweredDown(void)
+{
+  if (SupportsPowerDown() && Setup.PowerdownEnabled) {
+     cMutexLock MutexLock(&mutexPowerSaving);
+     return IsPoweredDown();
+     }
+  else
+     return false;
+}
+
+void cDevice::PowerUp(int ExtraTimeoutS)
+{
+  cMutexLock MutexLock(&mutexPowerSaving);
+  SetIdleTimer(true, ExtraTimeoutS);
+  if (SupportsPowerDown() && IsPoweredDown())
+     PowerDown(false);
+}
+
 // --- cTSBuffer -------------------------------------------------------------
cTSBuffer::cTSBuffer(int File, int Size, int CardIndex)
diff --git a/device.h b/device.h
index 31ee303..6c1fdfb 100644
--- a/device.h
+++ b/device.h
@@ -821,6 +821,35 @@ public:
        ///< Detaches all receivers from this device for this pid.
   virtual void DetachAllReceivers(void);
        ///< Detaches all receivers from this device.
+
+// Power saving facilities
+
+private:
+  cMutex mutexPowerSaving;
+  time_t idleTimerExpires, wakeupTimerExpires;
+  void PowerUp(int ExtraTimeoutS);
+       ///< If the device is powered down, powers it up and keeps it
+       ///< powered up for at least ExtraTimeoutS seconds (see
+       ///< cDevice::SetIdleTimer()).
+public:
+  void CheckIdle(void);
+       ///< Should be called periodically in the main loop.
+  bool PoweredDown(void);
+       ///< Returns true if the device is powered down "logically", that is,
+       ///< idle tasks like EPG scanning are disabled.
+  void SetIdleTimer(bool On, int ExtraTimeoutS = 0);
+       ///< Starts/disables the idle timer. This timer must be started when
+       ///< a device gets idle and must be disabled when it is receiving.
+       ///< If ExtraTimeoutS is greater than zero and On is true, a new timer
+       ///< won't be set, but the device will be kept powered up for at least
+       ///< ExtraTimeoutS seconds.
+protected:
+  virtual bool IsPoweredDown(void) {return false;}
+       ///< Returns true if the device is powered down "physically".
+  virtual void PowerDown(bool On) {};
+       ///< Actually powers the device down/up.
+  virtual bool SupportsPowerDown() {return false;}
+       ///< Returns true if a derived device supports power saving.
   };
/// Derived cDevice classes that can receive channels will have to provide
diff --git a/dvbdevice.c b/dvbdevice.c
index 63af52e..cdadbff 100644
--- a/dvbdevice.c
+++ b/dvbdevice.c
@@ -348,6 +348,8 @@ public:
   const cPositioner *Positioner(void) const { return positioner; }
   int GetSignalStrength(void) const;
   int GetSignalQuality(void) const;
+  bool IsPoweredDown(void) {return fd_frontend < 0;}
+  void PowerDown(bool On);
   };
cMutex cDvbTuner::bondMutex;
@@ -544,6 +546,8 @@ void cDvbTuner::ClearEventQueue(void) const
bool cDvbTuner::GetFrontendStatus(fe_status_t &Status) const
 {
+  if (fd_frontend < 0)
+     return false;
   ClearEventQueue();
   while (1) {
         if (ioctl(fd_frontend, FE_READ_STATUS, &Status) != -1)
@@ -559,6 +563,8 @@ bool cDvbTuner::GetFrontendStatus(fe_status_t &Status) const
int cDvbTuner::GetSignalStrength(void) const
 {
+  if (fd_frontend < 0)
+     return -1;
   ClearEventQueue();
   uint16_t Signal;
   while (1) {
@@ -1001,6 +1007,26 @@ void cDvbTuner::Action(void)
         }
 }
+void cDvbTuner::PowerDown(bool On)
+{
+  cMutexLock MutexLock(&mutex);
+  if (On && fd_frontend >= 0) {
+     isyslog("dvb tuner: power-down - closing frontend %d/%d",
adapter, frontend);
+     tunerStatus = tsIdle;
+     close(fd_frontend);
+     fd_frontend = -1;
+     }
+  if (!On && fd_frontend < 0) {
+     cString Filename = cString::sprintf("%s/%s%d/%s%d",
+        DEV_DVB_BASE, DEV_DVB_ADAPTER, adapter, DEV_DVB_FRONTEND, frontend);
+     isyslog("dvb tuner: power-up - opening frontend %d/%d", adapter,
frontend);
+     fd_frontend = open(Filename, O_RDWR | O_NONBLOCK);
+     if (fd_frontend < 0)
+        esyslog("ERROR: can't open DVB device frontend %d/%d",
adapter, frontend);
+     tunerStatus = tsIdle;
+     }
+}
+
 // --- cDvbSourceParam -------------------------------------------------------
class cDvbSourceParam : public cSourceParam {
@@ -1712,6 +1738,19 @@ void cDvbDevice::DetachAllReceivers(void)
   needsDetachBondedReceivers = false;
 }
+bool cDvbDevice::IsPoweredDown(void)
+{
+  if (dvbTuner)
+     return dvbTuner->IsPoweredDown();
+  return false;
+}
+
+void cDvbDevice::PowerDown(bool On)
+{
+  if (dvbTuner)
+     dvbTuner->PowerDown(On);
+}
+
 // --- cDvbDeviceProbe -------------------------------------------------------
cList<cDvbDeviceProbe> DvbDeviceProbes;
diff --git a/dvbdevice.h b/dvbdevice.h
index 5ae4952..15d1ff8 100644
--- a/dvbdevice.h
+++ b/dvbdevice.h
@@ -290,6 +290,13 @@ protected:
   virtual void CloseDvr(void);
   virtual bool GetTSPacket(uchar *&Data);
   virtual void DetachAllReceivers(void);
+
+// Power saving facilities
+
+protected:
+  virtual bool IsPoweredDown(void);
+  virtual void PowerDown(bool On);
+  virtual bool SupportsPowerDown() {return true;}
   };
// A plugin that implements a DVB device derived from cDvbDevice
needs to create
diff --git a/eitscan.c b/eitscan.c
index 41ac25e..765055c 100644
--- a/eitscan.c
+++ b/eitscan.c
@@ -144,7 +144,8 @@ void cEITScanner::Process(void)
            bool AnyDeviceSwitched = false;
            for (int i = 0; i < cDevice::NumDevices(); i++) {
                cDevice *Device = cDevice::GetDevice(i);
-               if (Device && Device->ProvidesEIT()) {
+               if (Device && Device->ProvidesEIT()
+                     && (!Device->PoweredDown() || lastActivity ==
0)) { // powered up or forced scan
                   for (cScanData *ScanData = scanList->First();
ScanData; ScanData = scanList->Next(ScanData)) {
                       const cChannel *Channel = ScanData->GetChannel();
                       if (Channel) {
@@ -165,6 +166,10 @@ void cEITScanner::Process(void)
                                            }
                                         }
                                      //dsyslog("EIT scan: device %d
source  %-8s tp %5d", Device->DeviceNumber() + 1,
*cSource::ToString(Channel->Source()), Channel->Transponder());
+                                     if (lastActivity == 0)
+                                        // forced scan - set idle
timer for each channel switch;
+                                        // this prevents powering
down while scanning a transponder
+                                        Device->SetIdleTimer(true,
ScanTimeout + 5);
                                      Device->SwitchChannel(Channel, false);
                                      scanList->Del(ScanData);
                                      AnyDeviceSwitched = true;
diff --git a/menu.c b/menu.c
index 569900c..5a89771 100644
--- a/menu.c
+++ b/menu.c
@@ -3715,6 +3715,12 @@ void cMenuSetupLNB::Setup(void)
      Add(new cMenuEditIntxItem(tr("Setup.LNB$Positioner speed
(degrees/s)"), &data.PositionerSpeed, 1, 1800, 10));
      }
+  Add(new cMenuEditBoolItem(tr("Setup.LNB$Enable power saving"),
&data.PowerdownEnabled));
+  if (data.PowerdownEnabled) {
+     Add(new cMenuEditIntItem(tr("Setup.LNB$Power down an idle device
after (min)"), &data.PowerdownTimeoutM));
+     Add(new cMenuEditIntItem(tr("Setup.LNB$Wake up from power-down
after (h)"), &data.PowerdownWakeupH));
+     }
+
   SetCurrent(Get(current));
   Display();
 }
@@ -3723,6 +3729,7 @@ eOSState cMenuSetupLNB::ProcessKey(eKeys Key)
 {
   int oldDiSEqC = data.DiSEqC;
   int oldUsePositioner = data.UsePositioner;
+  int oldPowerdownEnabled = data.PowerdownEnabled;
   bool DeviceBondingsChanged = false;
   if (Key == kOk) {
      cString NewDeviceBondings = satCableNumbers.ToString();
@@ -3731,7 +3738,7 @@ eOSState cMenuSetupLNB::ProcessKey(eKeys Key)
      }
   eOSState state = cMenuSetupBase::ProcessKey(Key);
-  if (Key != kNone && (data.DiSEqC != oldDiSEqC || data.UsePositioner
!= oldUsePositioner))
+  if (Key != kNone && (data.DiSEqC != oldDiSEqC || data.UsePositioner
!= oldUsePositioner || data.PowerdownEnabled != oldPowerdownEnabled))
      Setup();
   else if (DeviceBondingsChanged)
      cDvbDevice::BondDevices(data.DeviceBondings);
diff --git a/vdr.c b/vdr.c
index 6b0bf2b..c8de702 100644
--- a/vdr.c
+++ b/vdr.c
@@ -1515,6 +1515,12 @@ int main(int argc, char *argv[])
ReportEpgBugFixStats();
+        for (int i = 0; i < cDevice::NumDevices(); i++) {
+           cDevice *d = cDevice::GetDevice(i);
+           if (d)
+              d->CheckIdle();
+           }
+
         // Main thread hooks of plugins:
         PluginManager.MainThreadHook();
         }
-- 
1.9.1


    

[PATCH] Device power saving feature