CPU (Linux): bing cpuMHz back

It's used in WSL

Author: CarterLi

src/detection/cpu/cpu_linux.c

@@ -26,7 +26,7 @@ static void detectAndroid(FFCPUResult* cpu)
 }
 #endif
 
-static const char* parseCpuInfo(FFCPUResult* cpu, FFstrbuf* physicalCoresBuffer, FFstrbuf* cpuIsa, FFstrbuf* cpuUarch)
+static const char* parseCpuInfo(FFCPUResult* cpu, FFstrbuf* physicalCoresBuffer, FFstrbuf* cpuMHz, FFstrbuf* cpuIsa, FFstrbuf* cpuUarch)
 {
     FF_AUTO_CLOSE_FILE FILE* cpuinfo = fopen("/proc/cpuinfo", "r");
     if(cpuinfo == NULL)
@@ -49,6 +49,7 @@ static const char* parseCpuInfo(FFCPUResult* cpu, FFstrbuf* physicalCoresBuffer,
             ffParsePropLine(line, "model name :", &cpu->name) ||
             ffParsePropLine(line, "vendor_id :", &cpu->vendor) ||
             ffParsePropLine(line, "cpu cores :", physicalCoresBuffer) ||
+            ffParsePropLine(line, "cpu MHz :", cpuMHz) ||
             ffParsePropLine(line, "isa :", cpuIsa) ||
             ffParsePropLine(line, "uarch :", cpuUarch) ||
 
@@ -232,18 +233,19 @@ const char* ffDetectCPUImpl(const FFCPUOptions* options, FFCPUResult* cpu)
     cpu->temperature = options->temp ? detectCPUTemp() : FF_CPU_TEMP_UNSET;
 
     FF_STRBUF_AUTO_DESTROY physicalCoresBuffer = ffStrbufCreate();
+    FF_STRBUF_AUTO_DESTROY cpuMHz = ffStrbufCreate();
     FF_STRBUF_AUTO_DESTROY cpuIsa = ffStrbufCreate();
     FF_STRBUF_AUTO_DESTROY cpuUarch = ffStrbufCreate();
 
-    const char* error = parseCpuInfo(cpu, &physicalCoresBuffer, &cpuIsa, &cpuUarch);
+    const char* error = parseCpuInfo(cpu, &physicalCoresBuffer, &cpuMHz, &cpuIsa, &cpuUarch);
     if (error) return error;
 
     cpu->coresLogical = (uint16_t) get_nprocs_conf();
     cpu->coresOnline = (uint16_t) get_nprocs();
     cpu->coresPhysical = (uint16_t) ffStrbufToUInt(&physicalCoresBuffer, cpu->coresLogical);
 
-    detectFrequency(cpu);
-    // cpu MHz is current frequency, not max or base
+    if (!detectFrequency(cpu) || cpu->frequencyBase != cpu->frequencyBase)
+        cpu->frequencyBase = ffStrbufToDouble(&cpuMHz) / 1000;
 
     if(cpuUarch.length > 0)
     {