From aa2f6bf92b4bc911ec726381e7e5579d7399b376 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Sch=C3=BCrmann?= <daschuer@mixxx.org>
Date: Wed, 3 Jul 2013 00:30:47 +0200
Subject: [PATCH 1/2] check for rlimits on Linux

---
 build/depends.py       |  1 +
 src/dlgprefsound.cpp   | 11 +++++++++++
 src/dlgprefsounddlg.ui | 17 ++++++++++++-----
 src/util/rlimit.cpp    | 35 +++++++++++++++++++++++++++++++++++
 src/util/rlimit.h      | 14 ++++++++++++++
 5 files changed, 73 insertions(+), 5 deletions(-)
 create mode 100644 src/util/rlimit.cpp
 create mode 100644 src/util/rlimit.h

diff --git a/build/depends.py b/build/depends.py
index bb89ca6c478..40918539803 100644
--- a/build/depends.py
+++ b/build/depends.py
@@ -736,6 +736,7 @@ def sources(self, build):
                    "util/timer.cpp",
                    "util/performancetimer.cpp",
                    "util/version.cpp",
+                   "util/rlimit.cpp", 
 
                    # Add the QRC file which compiles in some extra resources
                    # (prefs icons, etc.)
diff --git a/src/dlgprefsound.cpp b/src/dlgprefsound.cpp
index 5578bd4af41..920c6a6282f 100644
--- a/src/dlgprefsound.cpp
+++ b/src/dlgprefsound.cpp
@@ -21,6 +21,7 @@
 #include "playermanager.h"
 #include "soundmanager.h"
 #include "sounddevice.h"
+#include "util/rlimit.h"
 
 /**
  * Construct a new sound preferences pane. Initializes and populates all the
@@ -100,6 +101,16 @@ DlgPrefSound::DlgPrefSound(QWidget *pParent, SoundManager *pSoundManager,
                     new ControlObjectThreadMain("[Master]", "latency");
     connect(m_pMasterLatency, SIGNAL(valueChanged(double)),
             this, SLOT(masterLatencyChanged(double)));
+
+    qDebug() << "RLimit Cur " << RLimit::getCurRtPrio();
+    qDebug() << "RLimit Max " << RLimit::getMaxRtPrio();
+
+#ifdef __LINUX__
+    if (RLimit::isRtPrioAllowed())
+#endif // __LINUX__
+    {
+        limitsHint->hide();
+    }
 }
 
 DlgPrefSound::~DlgPrefSound() {
diff --git a/src/dlgprefsounddlg.ui b/src/dlgprefsounddlg.ui
index d5eb133de77..910d8cf4dee 100644
--- a/src/dlgprefsounddlg.ui
+++ b/src/dlgprefsounddlg.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>729</width>
-    <height>363</height>
+    <width>743</width>
+    <height>369</height>
    </rect>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout_2">
@@ -106,9 +106,6 @@
        </item>
       </layout>
      </item>
-     <item>
-      <layout class="QHBoxLayout" name="underflowHLayout"/>
-     </item>
     </layout>
    </item>
    <item>
@@ -127,6 +124,16 @@
         </property>
        </widget>
       </item>
+      <item>
+       <widget class="QLabel" name="limitsHint">
+        <property name="text">
+         <string>&lt;ul&gt;&lt;li&gt;Enable Real-Time scheduling (currently disabled) see the &lt;a href=&quot;http://www.mixxx.org/wiki/doku.php/troubleshooting?s[]=limits&quot;&gt;Mixxx Wiki&lt;/a&gt;&lt;/li&gt;&lt;/ul&gt;</string>
+        </property>
+        <property name="openExternalLinks">
+         <bool>true</bool>
+        </property>
+       </widget>
+      </item>
      </layout>
     </widget>
    </item>
diff --git a/src/util/rlimit.cpp b/src/util/rlimit.cpp
new file mode 100644
index 00000000000..ed53ae68083
--- /dev/null
+++ b/src/util/rlimit.cpp
@@ -0,0 +1,35 @@
+#include "rlimit.h"
+
+#ifdef __LINUX__
+
+extern "C" {
+    #include <sys/time.h>
+    #include <sys/resource.h>
+}
+
+// static
+unsigned int RLimit::getCurRtPrio() {
+    struct rlimit limits;
+    if(getrlimit(RLIMIT_RTPRIO, &limits)) {
+        // Error
+        return 100;
+    }
+    return limits.rlim_cur;
+}
+
+// static
+unsigned int RLimit::getMaxRtPrio() {
+    struct rlimit limits;
+    if(getrlimit(RLIMIT_RTPRIO, &limits)) {
+        // Error
+        return 0;
+    }
+    return limits.rlim_max;
+}
+
+// static
+bool RLimit::isRtPrioAllowed() {
+    return (getCurRtPrio() >= 82); // PA sets RtPrio = 82
+}
+
+#endif // __LINUX__
diff --git a/src/util/rlimit.h b/src/util/rlimit.h
new file mode 100644
index 00000000000..d96fc88e4e8
--- /dev/null
+++ b/src/util/rlimit.h
@@ -0,0 +1,14 @@
+#ifndef RLIMIT_H
+#define RLIMIT_H
+
+#ifdef __LINUX__
+
+class RLimit {
+  public:
+    static unsigned int getCurRtPrio();
+    static unsigned int getMaxRtPrio();
+    static bool isRtPrioAllowed();
+};
+
+#endif // __LINUX__
+#endif // RLIMIT_H_

From abfba17b80b5d8bc23d3681b7edd541909ce071e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Sch=C3=BCrmann?= <daschuer@mixxx.org>
Date: Wed, 3 Jul 2013 19:56:48 +0200
Subject: [PATCH 2/2] minor fixes according to review comments

---
 src/util/rlimit.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/util/rlimit.cpp b/src/util/rlimit.cpp
index ed53ae68083..088f9157046 100644
--- a/src/util/rlimit.cpp
+++ b/src/util/rlimit.cpp
@@ -1,4 +1,4 @@
-#include "rlimit.h"
+#include "util/rlimit.h"
 
 #ifdef __LINUX__
 
@@ -7,6 +7,10 @@ extern "C" {
     #include <sys/resource.h>
 }
 
+// TODO(xxx) this is the result from a calculation inside PortAudio
+// We should query the value from PA or do the same calculations
+const rlim_t PA_RTPRIO = 82; // PA sets RtPrio = 82
+
 // static
 unsigned int RLimit::getCurRtPrio() {
     struct rlimit limits;
@@ -29,7 +33,7 @@ unsigned int RLimit::getMaxRtPrio() {
 
 // static
 bool RLimit::isRtPrioAllowed() {
-    return (getCurRtPrio() >= 82); // PA sets RtPrio = 82
+    return (getCurRtPrio() >= PA_RTPRIO); // PA sets RtPrio = 82
 }
 
 #endif // __LINUX__