From 6f7d38bbe5d7b13c84987cf3b3b550a11c39392e Mon Sep 17 00:00:00 2001
From: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Date: Tue, 29 Jul 2014 13:49:05 +0200
Subject: [PATCH] Recognize bool values in sysfs

The type of libahci parameter ahci_em_messages was changed from int to
bool in kernel v3.13, which caused AHCI HBAs to not be detected
properly.

Reported-and-tested-by: Paul Boven <boven@jive.nl>
Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
---
 src/cntrl.c |  7 +++++--
 src/utils.c | 17 +++++++++++++++++
 src/utils.h | 17 +++++++++++++++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/src/cntrl.c b/src/cntrl.c
index 2e6509b..e5170a2 100644
--- a/src/cntrl.c
+++ b/src/cntrl.c
@@ -216,8 +216,11 @@ static unsigned int _ahci_em_messages(const char *path)
 	if (get_int(path, 0, "driver/module/parameters/ahci_em_messages") != 0)
 		return 1;
 
-	if (!get_int("", 0, "sys/module/libahci/parameters/ahci_em_messages"))
-		return 0;
+	/* parameter type changed from int to bool since kernel v3.13 */
+	if (!get_int("", 0, "sys/module/libahci/parameters/ahci_em_messages")) {
+		if (!get_bool("", 0, "sys/module/libahci/parameters/ahci_em_messages"))
+			return 0;
+	}
 
 	if (snprintf(buf, sizeof(buf), "%s/%s", path, "driver") < 0)
 		return 0;
diff --git a/src/utils.c b/src/utils.c
index 36e4147..fca00a8 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -86,6 +86,23 @@ char *get_text(const char *path, const char *name)
 }
 
 /*
+ * Function returns integer value (1 or 0) based on a boolean value ('Y' or 'N')
+ * read from a text file. See utils.h for details.
+ */
+int get_bool(const char *path, int defval, const char *name)
+{
+	char *p = get_text(path, name);
+	if (p) {
+		if (*p == 'Y')
+			defval = 1;
+		else if (*p == 'N')
+			defval = 0;
+		free(p);
+	}
+	return defval;
+}
+
+/*
  * Function returns 64-bit unsigned integer value read from a text file. See
  * utils.h for details.
  */
diff --git a/src/utils.h b/src/utils.h
index c982113..5a0a76c 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -111,6 +111,23 @@ uint64_t get_uint64(const char *path, uint64_t defval, const char *name);
 char *get_text(const char *path, const char *name);
 
 /**
+ * @brief Reads boolean value from a text file.
+ *
+ * This function assumes that the only text in a file is the requested value to
+ * read. The recognized boolean values are in the format 'Y' for True and 'N'
+ * for False. In case of an error while reading from file the function will
+ * return a value stored in defval argument.
+ *
+ * @param[in]      path           Path where a file is located.
+ * @param[in]      defval         Default value to be returned in case of error.
+ * @param[in]      name           Name of a file to be read.
+ *
+ * @return Value read from a file if successful, otherwise a value stored in
+ *         defval argument. 1 is returned for True, 0 for False.
+ */
+int get_bool(const char *path, int defval, const char *name);
+
+/**
  * @brief Writes a text to file.
  *
  * This function writes a text to a file and return the number of bytes written.
-- 
2.4.3