1 files changed, 166 insertions, 0 deletions
diff --git a/Documentation/laptops/dslm.c b/Documentation/laptops/dslm.c
new file mode 100644
index 00000000000..72ff290c5fc
--- /dev/null
+++ b/Documentation/laptops/dslm.c
@@ -0,0 +1,166 @@
+/*
+ * dslm.c
+ * Simple Disk Sleep Monitor
+ *  by Bartek Kania
+ * Licenced under the GPL
+ */
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <time.h>
+#include <string.h>
+#include <signal.h>
+#include <sys/ioctl.h>
+#include <linux/hdreg.h>
+
+#ifdef DEBUG
+#define D(x) x
+#else
+#define D(x)
+#endif
+
+int endit = 0;
+
+/* Check if the disk is in powersave-mode
+ * Most of the code is stolen from hdparm.
+ * 1 = active, 0 = standby/sleep, -1 = unknown */
+static int check_powermode(int fd)
+{
+    unsigned char args[4] = {WIN_CHECKPOWERMODE1,0,0,0};
+    int state;
+
+    if (ioctl(fd, HDIO_DRIVE_CMD, &args)
+	&& (args[0] = WIN_CHECKPOWERMODE2) /* try again with 0x98 */
+	&& ioctl(fd, HDIO_DRIVE_CMD, &args)) {
+	if (errno != EIO || args[0] != 0 || args[1] != 0) {
+	    state = -1; /* "unknown"; */
+	} else
+	    state = 0; /* "sleeping"; */
+    } else {
+	state = (args[2] == 255) ? 1 : 0;
+    }
+    D(printf(" drive state is:  %d\n", state));
+
+    return state;
+}
+
+static char *state_name(int i)
+{
+    if (i == -1) return "unknown";
+    if (i == 0) return "sleeping";
+    if (i == 1) return "active";
+
+    return "internal error";
+}
+
+static char *myctime(time_t time)
+{
+    char *ts = ctime(&time);
+    ts[strlen(ts) - 1] = 0;
+
+    return ts;
+}
+
+static void measure(int fd)
+{
+    time_t start_time;
+    int last_state;
+    time_t last_time;
+    int curr_state;
+    time_t curr_time = 0;
+    time_t time_diff;
+    time_t active_time = 0;
+    time_t sleep_time = 0;
+    time_t unknown_time = 0;
+    time_t total_time = 0;
+    int changes = 0;
+    float tmp;
+
+    printf("Starting measurements\n");
+
+    last_state = check_powermode(fd);
+    start_time = last_time = time(0);
+    printf("  System is in state %s\n\n", state_name(last_state));
+
+    while(!endit) {
+	sleep(1);
+	curr_state = check_powermode(fd);
+
+	if (curr_state != last_state || endit) {
+	    changes++;
+	    curr_time = time(0);
+	    time_diff = curr_time - last_time;
+
+	    if (last_state == 1) active_time += time_diff;
+	    else if (last_state == 0) sleep_time += time_diff;
+	    else unknown_time += time_diff;
+
+	    last_state = curr_state;
+	    last_time = curr_time;
+
+	    printf("%s: State-change to %s\n", myctime(curr_time),
+		   state_name(curr_state));
+	}
+    }
+    changes--; /* Compensate for SIGINT */
+
+    total_time = time(0) - start_time;
+    printf("\nTotal running time:  %lus\n", curr_time - start_time);
+    printf(" State changed %d times\n", changes);
+
+    tmp = (float)sleep_time / (float)total_time * 100;
+    printf(" Time in sleep state:   %lus (%.2f%%)\n", sleep_time, tmp);
+    tmp = (float)active_time / (float)total_time * 100;
+    printf(" Time in active state:  %lus (%.2f%%)\n", active_time, tmp);
+    tmp = (float)unknown_time / (float)total_time * 100;
+    printf(" Time in unknown state: %lus (%.2f%%)\n", unknown_time, tmp);
+}
+
+static void ender(int s)
+{
+    endit = 1;
+}
+
+static void usage(void)
+{
+    puts("usage: dslm [-w <time>] <disk>");
+    exit(0);
+}
+
+int main(int argc, char **argv)
+{
+    int fd;
+    char *disk = 0;
+    int settle_time = 60;
+
+    /* Parse the simple command-line */
+    if (argc == 2)
+	disk = argv[1];
+    else if (argc == 4) {
+	settle_time = atoi(argv[2]);
+	disk = argv[3];
+    } else
+	usage();
+
+    if (!(fd = open(disk, O_RDONLY|O_NONBLOCK))) {
+	printf("Can't open %s, because: %s\n", disk, strerror(errno));
+	exit(-1);
+    }
+
+    if (settle_time) {
+	printf("Waiting %d seconds for the system to settle down to "
+	       "'normal'\n", settle_time);
+	sleep(settle_time);
+    } else
+	puts("Not waiting for system to settle down");
+
+    signal(SIGINT, ender);
+
+    measure(fd);
+
+    close(fd);
+
+    return 0;
+}