Brightness (Linux): allow specifying busno for ddcutil

Ref: #580

Author: CarterLi

src/detection/brightness/brightness_linux.c

@@ -92,45 +92,88 @@ static const char* detectWithBacklight(FFlist* result)
 
 #include <ddcutil_c_api.h>
 
+typedef struct DdcutilData
+{
+    FF_LIBRARY_SYMBOL(ddca_open_display2)
+    FF_LIBRARY_SYMBOL(ddca_get_any_vcp_value_using_explicit_type)
+    FF_LIBRARY_SYMBOL(ddca_free_any_vcp_value)
+    FF_LIBRARY_SYMBOL(ddca_close_display)
+} DdcutilData;
+
+static void detectWithDdcciImpl(DdcutilData* data, FFlist* result, DDCA_Display_Info* dinfo)
+{
+    DDCA_Display_Handle handle;
+    if (data->ffddca_open_display2(dinfo->dref, false, &handle) >= 0)
+    {
+        DDCA_Any_Vcp_Value* vcpValue = NULL;
+        if (data->ffddca_get_any_vcp_value_using_explicit_type(handle, 0x10 /*brightness*/, DDCA_NON_TABLE_VCP_VALUE, &vcpValue) >= 0)
+        {
+            assert(vcpValue->value_type == DDCA_NON_TABLE_VCP_VALUE);
+            int current = VALREC_CUR_VAL(vcpValue), max = VALREC_MAX_VAL(vcpValue);
+            data->ffddca_free_any_vcp_value(vcpValue);
+
+            FFBrightnessResult* brightness = (FFBrightnessResult*) ffListAdd(result);
+            brightness->max = max;
+            brightness->min = 0;
+            brightness->current = current;
+            ffStrbufInitS(&brightness->name, dinfo->model_name);
+        }
+        data->ffddca_close_display(handle);
+    }
+}
+
 static const char* detectWithDdcci(FFlist* result)
 {
-    FF_LIBRARY_LOAD(libddcutil, &instance.config.libDdcutil, "dlopen ddcutil failed", "libddcutil" FF_LIBRARY_EXTENSION, 5);
+    FF_LIBRARY_LOAD(libddcutil, &instance.config.libDdcutil, "dlopen ddcutil failed", "libddcutil" FF_LIBRARY_EXTENSION, 5)
     FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_get_display_info_list2)
-    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_open_display2)
-    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_get_any_vcp_value_using_explicit_type)
-    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_free_any_vcp_value)
-    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_close_display)
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_get_display_info)
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_create_busno_display_identifier)
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_create_display_ref)
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_free_display_identifier)
+    FF_LIBRARY_LOAD_SYMBOL_MESSAGE(libddcutil, ddca_free_display_ref)
+
+    DdcutilData ddcutilData;
+    FF_LIBRARY_LOAD_SYMBOL_VAR_MESSAGE(libddcutil, ddcutilData, ddca_open_display2)
+    FF_LIBRARY_LOAD_SYMBOL_VAR_MESSAGE(libddcutil, ddcutilData, ddca_get_any_vcp_value_using_explicit_type)
+    FF_LIBRARY_LOAD_SYMBOL_VAR_MESSAGE(libddcutil, ddcutilData, ddca_free_any_vcp_value)
+    FF_LIBRARY_LOAD_SYMBOL_VAR_MESSAGE(libddcutil, ddcutilData, ddca_close_display)
     libddcutil = NULL; // Don't dlclose libddcutil. See https://github.com/rockowitz/ddcutil/issues/330
 
+    if (instance.config.brightness.busNos.length)
+    {
+        FF_SUPPRESS_IO();
+
+        FF_LIST_FOR_EACH(int, busno, instance.config.brightness.busNos)
+        {
+            DDCA_Display_Identifier did;
+            if (ffddca_create_busno_display_identifier(*busno, &did) >= 0)
+            {
+                DDCA_Display_Ref dref;
+                if (ffddca_create_display_ref(did, &dref) >= 0)
+                {
+                    FF_AUTO_FREE DDCA_Display_Info* dinfo = NULL;
+                    if (ffddca_get_display_info(dref, &dinfo) >= 0)
+                        detectWithDdcciImpl(&ddcutilData, result, dinfo);
+                    ffddca_free_display_ref(dref);
+                }
+
+                ffddca_free_display_identifier(did);
+            }
+        }
+
+        return NULL;
+    }
+
     FF_AUTO_FREE DDCA_Display_Info_List* infoList = NULL;
-    if (__builtin_expect(ffddca_get_display_info_list2(false, &infoList) < 0, 0))
+    if (ffddca_get_display_info_list2(false, &infoList) < 0)
         return "ddca_get_display_info_list2(false, &infoList) failed";
 
     if (infoList->ct == 0)
         return "No DDC/CI compatible displays found";
 
     for (int index = 0; index < infoList->ct; ++index)
     {
-        const DDCA_Display_Info* display = &infoList->info[index];
-
-        DDCA_Display_Handle handle;
-        if (ffddca_open_display2(display->dref, false, &handle) >= 0)
-        {
-            DDCA_Any_Vcp_Value* vcpValue = NULL;
-            if (ffddca_get_any_vcp_value_using_explicit_type(handle, 0x10 /*brightness*/, DDCA_NON_TABLE_VCP_VALUE, &vcpValue) >= 0)
-            {
-                assert(vcpValue->value_type == DDCA_NON_TABLE_VCP_VALUE);
-                int current = VALREC_CUR_VAL(vcpValue), max = VALREC_MAX_VAL(vcpValue);
-                ffddca_free_any_vcp_value(vcpValue);
-
-                FFBrightnessResult* brightness = (FFBrightnessResult*) ffListAdd(result);
-                brightness->max = max;
-                brightness->min = 0;
-                brightness->current = current;
-                ffStrbufInitS(&brightness->name, display->model_name);
-            }
-            ffddca_close_display(handle);
-        }
+        detectWithDdcciImpl(&ddcutilData, result, &infoList->info[index]);
     }
 
     return NULL;

src/modules/brightness/brightness.c

@@ -88,6 +88,10 @@ void ffInitBrightnessOptions(FFBrightnessOptions* options)
 {
     ffOptionInitModuleBaseInfo(&options->moduleInfo, FF_BRIGHTNESS_MODULE_NAME, ffParseBrightnessCommandOptions, ffParseBrightnessJsonObject, ffPrintBrightness, ffGenerateBrightnessJson, ffPrintBrightnessHelpFormat);
     ffOptionInitModuleArg(&options->moduleArgs);
+
+    #ifdef __linux__
+    ffListInit(&options->busNos, sizeof(int));
+    #endif
 }
 
 bool ffParseBrightnessCommandOptions(FFBrightnessOptions* options, const char* key, const char* value)
@@ -103,6 +107,10 @@ bool ffParseBrightnessCommandOptions(FFBrightnessOptions* options, const char* k
 void ffDestroyBrightnessOptions(FFBrightnessOptions* options)
 {
     ffOptionDestroyModuleArg(&options->moduleArgs);
+
+    #ifdef __linux__
+    ffListDestroy(&options->busNos);
+    #endif
 }
 
 void ffParseBrightnessJsonObject(FFBrightnessOptions* options, yyjson_val* module)
@@ -118,6 +126,22 @@ void ffParseBrightnessJsonObject(FFBrightnessOptions* options, yyjson_val* modul
         if (ffJsonConfigParseModuleArgs(key, val, &options->moduleArgs))
             continue;
 
+        #ifdef __linux__
+        if(ffStrEqualsIgnCase(key, "busNos"))
+        {
+            if (!yyjson_is_arr(val)) continue;
+
+            yyjson_val* item;
+            size_t idx, max;
+            yyjson_arr_foreach(val, idx, max, item)
+            {
+                if (!yyjson_is_int(item)) continue;
+                *(int*) ffListAdd(&options->busNos) = yyjson_get_int(item);
+            }
+            continue;
+        }
+        #endif
+
         ffPrintError(FF_BRIGHTNESS_MODULE_NAME, 0, &options->moduleArgs, "Unknown JSON key %s", key);
     }
 }

src/modules/brightness/option.h

@@ -8,4 +8,8 @@ typedef struct FFBrightnessOptions
 {
     FFModuleBaseInfo moduleInfo;
     FFModuleArgs moduleArgs;
+
+#ifdef __linux__
+    FFlist busNos;
+#endif
 } FFBrightnessOptions;