[PATCH] PM: HIBERNATION: add resume_wait param to support MMC-like devices as resume file

[Barry Song]

2011/10/7 Barry Song <21cnbao at gmail.com>:
> 2011/10/7 Pavel Machek <pavel at ucw.cz>:
>>> 2011/9/29 Luca Tettamanti <kronos.it at gmail.com>:
>>> > On Thu, Sep 29, 2011 at 11:29 AM, Barry Song <Barry.Song at csr.com> wrote:
>>> >> From: Barry Song <baohua.song at csr.com>
>>> >>
>>> >> 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.
>>> >
>>> > I assume that such a device would need "rootwait" to boot in the first
>>> > place; why don't you "overload" the param to also enable waiting in
>>> > the resume path?
>>>
>>> not real. for an embedded product, the type of the rootfs, the place
>>> of the rootfs  and the way to mount rootfs are pretty flexible.
>>> even though both rootfs and resume file use mmc, they will be in
>>> different partitions at least. so i don't think rootwait can overload
>>> resumewait.
>>
>> It would be good to at least model it the same way. rootdelay allows
>> you to specify time, which is important for USB devices...
>
> actually i considered resumedelay before i sent this resumewait patch.
> now resumedelay is not an indispensable feature to my application and
> most other systems since they are able to wait for the swap devices
> ready by resumewait.
> but of course we can have the resumedelay param as well just like
> rootdelay. since Rafael has applied this resumedelay patch,  i can

 sorry for typo.  -> since Rafael has applied this *resumewait* patch

> treat resumedelay as one new seperate patch.
>
>>
>> --
>> (english) http://www.livejournal.com/~pavelmachek
>> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
>>
> -barry
>