lib/igt_eld: introduce an ELD library

new file mode 100644
index 000000000000..8e0dcc306e85
@@ -0,0 +1,111 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors: Simon Ser <[email protected]>
+ */
+
+#include "config.h"
+
+#include <dirent.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "igt_eld.h"
+
+/**
+ * EDID-Like Data (ELD) is metadata parsed and exposed by ALSA for HDMI and
+ * DisplayPort connectors supporting audio. This includes the monitor name and
+ * the supported audio parameters (formats, sampling rates, sample sizes and so
+ * on).
+ */
+
+/** eld_entry_is_igt: checks whether an ELD entry is mapped to the IGT EDID */
+static bool eld_entry_is_igt(const char *path)
+{
+	FILE *in;
+	char buf[1024];
+	uint8_t eld_valid = 0;
+	uint8_t mon_valid = 0;
+
+	in = fopen(path, "r");
+	if (!in)
+		return false;
+
+	memset(buf, 0, 1024);
+
+	while ((fgets(buf, 1024, in)) != NULL) {
+		char *line = buf;
+
+		if (!strncasecmp(line, "eld_valid", 9) &&
+				strstr(line, "1")) {
+			eld_valid++;
+		}
+
+		if (!strncasecmp(line, "monitor_name", 12) &&
+				strstr(line, "IGT")) {
+			mon_valid++;
+		}
+	}
+
+	fclose(in);
+	if (mon_valid && eld_valid)
+		return true;
+
+	return false;
+}
+
+/** eld_has_igt: check whether ALSA has detected the audio-capable IGT EDID by
+ * parsing ELD entries */
+bool eld_has_igt(void)
+{
+	DIR *dir;
+	struct dirent *snd_hda;
+	int i;
+
+	for (i = 0; i < 8; i++) {
+		char cards[128];
+
+		snprintf(cards, sizeof(cards), "/proc/asound/card%d", i);
+		dir = opendir(cards);
+		if (!dir)
+			continue;
+
+		while ((snd_hda = readdir(dir))) {
+			char fpath[PATH_MAX];
+
+			if (*snd_hda->d_name == '.' ||
+			    strstr(snd_hda->d_name, "eld") == 0)
+				continue;
+
+			snprintf(fpath, sizeof(fpath), "%s/%s", cards,
+				 snd_hda->d_name);
+			if (eld_entry_is_igt(fpath)) {
+				closedir(dir);
+				return true;
+			}
+		}
+		closedir(dir);
+	}
+
+	return false;
+}

new file mode 100644
index 000000000000..844b8027d047
@@ -0,0 +1,35 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors: Simon Ser <[email protected]>
+ */
+
+#ifndef IGT_EDID_H
+#define IGT_EDID_H
+
+#include "config.h"
+
+#include <stdbool.h>
+
+bool eld_has_igt(void);
+
+#endif

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index 8e0dcc306e85..6dbc885ffa23 100644
@@ -30,8 +30,12 @@
 #include <stdio.h>
 #include <string.h>
 
+#include "igt_core.h"
 #include "igt_eld.h"
 
+#define ELD_PREFIX "eld#"
+#define ELD_DELIM " \t"
+
 /**
  * EDID-Like Data (ELD) is metadata parsed and exposed by ALSA for HDMI and
  * DisplayPort connectors supporting audio. This includes the monitor name and

@@ -39,39 +43,47 @@
  * on).
  */
 
-/** eld_entry_is_igt: checks whether an ELD entry is mapped to the IGT EDID */
-static bool eld_entry_is_igt(const char *path)
+static bool eld_parse_entry(const char *path, struct eld_entry *eld)
 {
-	FILE *in;
+	FILE *f;
 	char buf[1024];
-	uint8_t eld_valid = 0;
-	uint8_t mon_valid = 0;
-
-	in = fopen(path, "r");
-	if (!in)
-		return false;
+	char *key, *value;
+	size_t len;
+	bool monitor_present;
 
-	memset(buf, 0, 1024);
+	memset(eld, 0, sizeof(*eld));
 
-	while ((fgets(buf, 1024, in)) != NULL) {
-		char *line = buf;
+	f = fopen(path, "r");
+	if (!f) {
+		igt_debug("Failed to open ELD file: %s\n", path);
+		return false;
+	}
 
-		if (!strncasecmp(line, "eld_valid", 9) &&
-				strstr(line, "1")) {
-			eld_valid++;
-		}
+	while ((fgets(buf, sizeof(buf), f)) != NULL) {
+		len = strlen(buf);
+		if (buf[len - 1] == '\n')
+			buf[len - 1] = '\0';
+
+		key = strtok(buf, ELD_DELIM);
+		value = strtok(NULL, ELD_DELIM);
+
+		if (strcmp(key, "monitor_present") == 0)
+			monitor_present = strcmp(value, "1") == 0;
+		else if (strcmp(key, "eld_valid") == 0)
+			eld->valid = strcmp(value, "1") == 0;
+		else if (strcmp(key, "monitor_name") == 0)
+			snprintf(eld->monitor_name, sizeof(eld->monitor_name),
+				 "%s", value);
+	}
 
-		if (!strncasecmp(line, "monitor_name", 12) &&
-				strstr(line, "IGT")) {
-			mon_valid++;
-		}
+	if (ferror(f) != 0) {
+		igt_debug("Failed to read ELD file: %d\n", ferror(f));
+		return false;
 	}
 
-	fclose(in);
-	if (mon_valid && eld_valid)
-		return true;
+	fclose(f);
 
-	return false;
+	return monitor_present;
 }
 
 /** eld_has_igt: check whether ALSA has detected the audio-capable IGT EDID by

@@ -79,27 +91,35 @@ static bool eld_entry_is_igt(const char *path)
 bool eld_has_igt(void)
 {
 	DIR *dir;
-	struct dirent *snd_hda;
+	struct dirent *dirent;
 	int i;
+	char card[64];
+	char path[PATH_MAX];
+	struct eld_entry eld;
 
 	for (i = 0; i < 8; i++) {
-		char cards[128];
-
-		snprintf(cards, sizeof(cards), "/proc/asound/card%d", i);
-		dir = opendir(cards);
+		snprintf(card, sizeof(card), "/proc/asound/card%d", i);
+		dir = opendir(card);
 		if (!dir)
 			continue;
 
-		while ((snd_hda = readdir(dir))) {
-			char fpath[PATH_MAX];
+		while ((dirent = readdir(dir))) {
+			if (strncmp(dirent->d_name, ELD_PREFIX,
+				    strlen(ELD_PREFIX)) != 0)
+				continue;
+
+			snprintf(path, sizeof(path), "%s/%s", card,
+				 dirent->d_name);
+			if (!eld_parse_entry(path, &eld)) {
+				continue;
+			}
 
-			if (*snd_hda->d_name == '.' ||
-			    strstr(snd_hda->d_name, "eld") == 0)
+			if (!eld.valid) {
+				igt_debug("Skipping invalid ELD: %s\n", path);
 				continue;
+			}
 
-			snprintf(fpath, sizeof(fpath), "%s/%s", cards,
-				 snd_hda->d_name);
-			if (eld_entry_is_igt(fpath)) {
+			if (strcmp(eld.monitor_name, "IGT") == 0) {
 				closedir(dir);
 				return true;
 			}

index 844b8027d047..ea09040e8325 100644
@@ -30,6 +30,11 @@
 
 #include <stdbool.h>
 
+struct eld_entry {
+	bool valid;
+	char monitor_name[16];
+};
+
 bool eld_has_igt(void);
 
 #endif