Patchset related to hibernation resume: one enhancement to make the use of an existing file more general and one documentation update.
Both patches are based on the 3.11-rc6 tag. This was tested on a Pandaboard with partial hibernation support, and compiled on x86.
Further testing is needed on other platforms. Please let me know if you're able to verify this on any other systems.
[PATCH 1/2] PM / Hibernate: use name_to_dev_t to parse resume Use name_to_dev_t to parse the /sys/power/resume file making the syntax more flexible. It supports the previous use syntax and additionally can support other formats such as /dev/devicenode and UUID= formats.
By changing /sys/debug/resume to accept the same syntax as the resume=device parameter, we can parse the resume=device in the initrd init script and use the resume device directly from the kernel command line.
kernel/power/hibernate.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)
[PATCH 2/2] PM / Hibernate: add section for resume options This adds a small section to the swsusp.txt file to address the options for resuming. This comments on the manual resume option which is used when resorting to an initrd or initramfs for resuming. Resuming from late init is discussed later in the document, but it seemed appropriate to list them together.
Documentation/power/swsusp.txt | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
Changes in v2: --------------
* Added check for null return of kstrndup in hibernate.c
Thanks,
Sebastian
Use the name_to_dev_t call to parse the device name echo'd to to /sys/power/resume. This imitates the method used in hibernate.c in software_resume, and allows the resume partition to be specified using other equivalent device formats as well. By allowing /sys/debug/resume to accept the same syntax as the resume=device parameter, we can parse the resume=device in the init script and use the resume device directly from the kernel command line.
Signed-off-by: Sebastian Capella sebastian.capella@linaro.org Cc: Len Brown len.brown@intel.com Cc: Pavel Machek pavel@ucw.cz Cc: "Rafael J. Wysocki" rjw@sisk.pl --- kernel/power/hibernate.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index b26f5f1..8ba8719 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -971,15 +971,23 @@ static ssize_t resume_show(struct kobject *kobj, struct kobj_attribute *attr, static ssize_t resume_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t n) { - unsigned int maj, min; dev_t res; int ret = -EINVAL; + int len = n; + char *devcpy;
- if (sscanf(buf, "%u:%u", &maj, &min) != 2) - goto out; + if (buf[len-1] == '\n') + len--; + + devcpy = kstrndup(buf, len, GFP_KERNEL); + + if (devcpy == NULL) + return -ENOMEM; + + res = name_to_dev_t(devcpy); + kfree(devcpy);
- res = MKDEV(maj,min); - if (maj != MAJOR(res) || min != MINOR(res)) + if (res == 0) goto out;
lock_system_sleep();
Expand the existing documentation to explicitly list the options for resuming a hibernation image, including the manual resume option which can be used from the initrd or initramfs and the kernel init resume.
Signed-off-by: Sebastian Capella sebastian.capella@linaro.org Cc: Rob Landley rob@landley.net Cc: Len Brown len.brown@intel.com Cc: Pavel Machek pavel@ucw.cz Cc: "Rafael J. Wysocki" rjw@sisk.pl --- Documentation/power/swsusp.txt | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt index 0b4b63e..079160e 100644 --- a/Documentation/power/swsusp.txt +++ b/Documentation/power/swsusp.txt @@ -50,6 +50,19 @@ echo N > /sys/power/image_size
before suspend (it is limited to 500 MB by default).
+. The resume process checks for the presence of the resume device, +if found, it then checks the contents for the hibernation image signature. +If both are found, it resumes the hibernation image. + +. The resume process may be triggered in two ways: + 1) During lateinit: If resume=/dev/your_swap_partition is specified on + the kernel command line, lateinit runs the resume process. If the + resume device has not been probed yet, the resume process fails and + bootup continues. + 2) Manually from an initrd or initramfs: May be run from + the init script by using the /sys/power/resume file. It is vital + that this be done prior to remounting any filesystems (even as + read-only) otherwise data may be corrupted.
Article about goals and implementation of Software Suspend for Linux ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -326,7 +339,7 @@ Q: How can distributions ship a swsusp-supporting kernel with modular disk drivers (especially SATA)?
A: Well, it can be done, load the drivers, then do echo into -/sys/power/disk/resume file from initrd. Be sure not to mount +/sys/power/resume file from initrd. Be sure not to mount anything, not even read-only mount, or you are going to lose your data.
Hi!
On Tue 2013-08-27 18:13:57, Sebastian Capella wrote:
Expand the existing documentation to explicitly list the options for resuming a hibernation image, including the manual resume option which can be used from the initrd or initramfs and the kernel init resume.
...it also fixes sysfs path in second hunk.
Signed-off-by: Sebastian Capella sebastian.capella@linaro.org Cc: Rob Landley rob@landley.net Cc: Len Brown len.brown@intel.com Cc: Pavel Machek pavel@ucw.cz
Acked-by: Pavel Machek pavel@ucw.cz
(Cc-ed trivial so this does not get lost).
@@ -326,7 +339,7 @@ Q: How can distributions ship a swsusp-supporting kernel with modular disk drivers (especially SATA)? A: Well, it can be done, load the drivers, then do echo into -/sys/power/disk/resume file from initrd. Be sure not to mount +/sys/power/resume file from initrd. Be sure not to mount anything, not even read-only mount, or you are going to lose your data.
-
Pavel Machek -
Sebastian Capella