PM / Hibernate: Add resumedelay kernel param in addition to resumewait

Patch "PM / Hibernate: Add resumewait param to support MMC-like
devices as resume file" added the resumewait kernel command line
option.  The present patch adds resumedelay so that
resumewait/delay were analogous to rootwait/delay.

[rjw: Modified the subject and changelog slightly.]
Signed-off-by: Barry Song <baohua.song@csr.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Documentation/kernel-parameters.txt

@@ -2240,6 +2240,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			in <PAGE_SIZE> units (needed only for swap files).
 			See  Documentation/power/swsusp-and-swap-files.txt
 
+	resumedelay=	[HIBERNATION] Delay (in seconds) to pause before attempting to
+			read the resume files
+
 	resumewait	[HIBERNATION] Wait (indefinitely) for resume device to show up.
 			Useful for devices that are detected asynchronously
 			(e.g. USB and MMC devices).

kernel/power/hibernate.c

@@ -33,6 +33,7 @@
 static int nocompress = 0;
 static int noresume = 0;
 static int resume_wait = 0;
+static int resume_delay = 0;
 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
 dev_t swsusp_resume_device;
 sector_t swsusp_resume_block;
@@ -730,6 +731,12 @@ static int software_resume(void)
 
 	pr_debug("PM: Checking hibernation image partition %s\n", resume_file);
 
+	if (resume_delay) {
+		printk(KERN_INFO "Waiting %dsec before reading resume device...\n",
+			resume_delay);
+		ssleep(resume_delay);
+	}
+
 	/* Check if the device is there */
 	swsusp_resume_device = name_to_dev_t(resume_file);
 	if (!swsusp_resume_device) {
@@ -1079,8 +1086,15 @@ static int __init resumewait_setup(char *str)
 	return 1;
 }
 
+static int __init resumedelay_setup(char *str)
+{
+	resume_delay = simple_strtoul(str, NULL, 0);
+	return 1;
+}
+
 __setup("noresume", noresume_setup);
 __setup("resume_offset=", resume_offset_setup);
 __setup("resume=", resume_setup);
 __setup("hibernate=", hibernate_setup);
 __setup("resumewait", resumewait_setup);
+__setup("resumedelay=", resumedelay_setup);