[igt-dev] [PATCH i-g-t 2/2] lib/igt_eld: consolidate ELD parsing

[Simon Ser]

Make the ELD enumeration more robust, and implement proper parsing for ELD
fields. This will become useful when other ELD fields (formats, sample rates,
sample sizes) will be parsed and checked.

Signed-off-by: Simon Ser <simon.ser at intel.com>
---
 lib/igt_eld.c | 92 +++++++++++++++++++++++++++++++--------------------
 lib/igt_eld.h |  5 +++
 2 files changed, 61 insertions(+), 36 deletions(-)

diff --git a/lib/igt_eld.c b/lib/igt_eld.c
index 8e0dcc306e85..6dbc885ffa23 100644
--- a/lib/igt_eld.c
+++ b/lib/igt_eld.c
@@ -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;
 			}
diff --git a/lib/igt_eld.h b/lib/igt_eld.h
index 844b8027d047..ea09040e8325 100644
--- a/lib/igt_eld.h
+++ b/lib/igt_eld.h
@@ -30,6 +30,11 @@
 
 #include <stdbool.h>
 
+struct eld_entry {
+	bool valid;
+	char monitor_name[16];
+};
+
 bool eld_has_igt(void);
 
 #endif
-- 
2.21.0