On Thursday, September 29, 2011, Barry Song wrote:
> From: Barry Song <baohua.song@xxxxxxx>
>
> Some devices like mmc are async detected very slow. For example,
> drivers/mmc/host/sdhci.c launchs a 200ms delayed work to detect
> mmc partitions then add disk.
>
> we do have wait_for_device_probe and scsi_complete_async_scans
> before calling swsusp_check, but it is not enough to wait mmc.
>
> This patch adds resumewait kernel param just like rootwait so
> that we have enough time to wait mmc ready. The differene is
> here we wait for resume partition but rootwait waits for rootfs
> partition.
>
> This patch will make swsusp support many embedded products
> without scsi devices but devices like mmc.
>
> This was tested on one ARM platform with Frank Hofmann's patch.
>
> Signed-off-by: Barry Song <Baohua.Song@xxxxxxx>
> Reviewed-by: Valdis Kletnieks <valdis.kletnieks@xxxxxx>
Sorry, I couldn't find the patch previously.
I only have one question. Namely, are there any systems that would
use resumewait and wouldn't use rootwait?
Rafael
> ---
> -v2:
> add document for the resumewait kernel parameter
>
> Documentation/kernel-parameters.txt | 4 ++++
> kernel/power/hibernate.c | 16 ++++++++++++++++
> 2 files changed, 20 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index 614d038..2aed0d2 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -2237,6 +2237,10 @@ 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
>
> + resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
> + Useful for devices that are detected asynchronously
> + (e.g. USB and MMC devices).
> +
> hibernate= [HIBERNATION]
> noresume Don't check if there's a hibernation image
> present during boot.
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index 8f7b1db..9f4b4f3 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -14,6 +14,7 @@
> #include <linux/reboot.h>
> #include <linux/string.h>
> #include <linux/device.h>
> +#include <linux/async.h>
> #include <linux/kmod.h>
> #include <linux/delay.h>
> #include <linux/fs.h>
> @@ -31,6 +32,7 @@
>
> static int nocompress = 0;
> static int noresume = 0;
> +static int resume_wait = 0;
> static char resume_file[256] = CONFIG_PM_STD_PARTITION;
> dev_t swsusp_resume_device;
> sector_t swsusp_resume_block;
> @@ -732,6 +734,13 @@ static int software_resume(void)
> * to wait for this to finish.
> */
> wait_for_device_probe();
> +
> + if (resume_wait) {
> + while ((swsusp_resume_device = name_to_dev_t(resume_file)) == 0)
> + msleep(10);
> + async_synchronize_full();
> + }
> +
> /*
> * We can't depend on SCSI devices being available after loading
> * one of their modules until scsi_complete_async_scans() is
> @@ -1060,7 +1069,14 @@ static int __init noresume_setup(char *str)
> return 1;
> }
>
> +static int __init resumewait_setup(char *str)
> +{
> + resume_wait = 1;
> + return 1;
> +}
> +
> __setup("noresume", noresume_setup);
> __setup("resume_offset=", resume_offset_setup);
> __setup("resume=", resume_setup);
> __setup("hibernate=", hibernate_setup);
> +__setup("resumewait", resumewait_setup);
>
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