PM with rootfs on mmc?

PM with rootfs on mmc?

[Sriram V]

Hi,
  I am trying to test pm on my platform/board.
  I am using the latest linux kernel - 2.6.28-rc6
  PM Support exists in my mmc driver and suspend and resume work fine.

  With rootfs mounted via NFS. I am able to do
   $ echo -n mem > /sys/power/state

  The above works. It successfully calls suspend and resume of sdmmc driver.

  However, the same does not work if i have mounted the SDMMC card
with rootfs on NFS.

  The kernel hangs, when i try to do
     $ echo -n mem > /sys/power/state

 In this case suspend and resume functions of the driver are not called
 at all. (I gave a couple of debug prints at the beginning of suspend and resume
 and they didnot get print)

 Same behaviour is observed when i boot out of SDMMC card. Suspend/Resume
 dont work. The kernel hangs.

I get the messages in both case when i suspend-to-ram.

PM: Syncing filesystems ... done.
Freezing user space processes ... (elapsed 0.00 seconds) done.
Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done.
Suspending console(s) (use no_console_suspend to debug)


I am not sure if this has to do with SD/MMC driver or something else.

Please advice.

Regards,
sriram

Re: PM with rootfs on mmc?

[Len Brown]

On Wed, 31 Dec 2008, Sriram V wrote:

> Hi,
>   I am trying to test pm on my platform/board.
>   I am using the latest linux kernel - 2.6.28-rc6
>   PM Support exists in my mmc driver and suspend and resume work fine.
> 
>   With rootfs mounted via NFS. I am able to do
>    $ echo -n mem > /sys/power/state
> 
>   The above works. It successfully calls suspend and resume of sdmmc driver.
> 
>   However, the same does not work if i have mounted the SDMMC card
> with rootfs on NFS.
> 
>   The kernel hangs, when i try to do
>      $ echo -n mem > /sys/power/state
> 
>  In this case suspend and resume functions of the driver are not called
>  at all. (I gave a couple of debug prints at the beginning of suspend and resume
>  and they didnot get print)
> 
>  Same behaviour is observed when i boot out of SDMMC card. Suspend/Resume
>  dont work. The kernel hangs.
> 
> I get the messages in both case when i suspend-to-ram.
> 
> PM: Syncing filesystems ... done.
> Freezing user space processes ... (elapsed 0.00 seconds) done.
> Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done.
> Suspending console(s) (use no_console_suspend to debug)
> 
> 
> I am not sure if this has to do with SD/MMC driver or something else.

What do you seen when you boot with "no_console_suspend"

You may also want to check out
Documentation/power/basic-pm-debugging.txt"

cheers,
-- Len Brown, Intel Open Source Technology Center

Re: PM with rootfs on mmc?

[Sriram V]

Hi,
   Now, i am able to bring linux out of suspend. The problem was to do
with the mmc card detection. With out card detection, The kernel used
to hang when i tried to
bring linux out of suspend.

The below works, if i boot out of NFS and mount sdmmc and do a

$ echo -n mem > /sys/power/state

However, If i boot out of SDMMC (rootfs on sdmmc). I am not able to
bring it out of suspend.
The kernel hangs.

I get the message:
# echo -n mem > /sys/power/state
PM: Syncing filesystems ... done.
Freezing user space processes ... (elapsed 0.00 seconds) done.
Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done.
mmc0: card e624 removed
--- kernel hangs---

Regards,
sriram






On Wed, Dec 31, 2008 at 11:53 AM, Len Brown <lenb@kernel.org> wrote:
>
>
>
>
> On Wed, 31 Dec 2008, Sriram V wrote:
>
>> Hi,
>>   I am trying to test pm on my platform/board.
>>   I am using the latest linux kernel - 2.6.28-rc6
>>   PM Support exists in my mmc driver and suspend and resume work fine.
>>
>>   With rootfs mounted via NFS. I am able to do
>>    $ echo -n mem > /sys/power/state
>>
>>   The above works. It successfully calls suspend and resume of sdmmc driver.
>>
>>   However, the same does not work if i have mounted the SDMMC card
>> with rootfs on NFS.
>>
>>   The kernel hangs, when i try to do
>>      $ echo -n mem > /sys/power/state
>>
>>  In this case suspend and resume functions of the driver are not called
>>  at all. (I gave a couple of debug prints at the beginning of suspend and resume
>>  and they didnot get print)
>>
>>  Same behaviour is observed when i boot out of SDMMC card. Suspend/Resume
>>  dont work. The kernel hangs.
>>
>> I get the messages in both case when i suspend-to-ram.
>>
>> PM: Syncing filesystems ... done.
>> Freezing user space processes ... (elapsed 0.00 seconds) done.
>> Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done.
>> Suspending console(s) (use no_console_suspend to debug)
>>
>>
>> I am not sure if this has to do with SD/MMC driver or something else.
>
> What do you seen when you boot with "no_console_suspend"
>
> You may also want to check out
> Documentation/power/basic-pm-debugging.txt"
>
> cheers,
> -- Len Brown, Intel Open Source Technology Center
>
>
>

Re: PM with rootfs on mmc?

[Pavel Machek]

On Wed 2008-12-31 21:02:06, Sriram V wrote:
> Hi,
>    Now, i am able to bring linux out of suspend. The problem was to do
> with the mmc card detection. With out card detection, The kernel used
> to hang when i tried to
> bring linux out of suspend.
> 
> The below works, if i boot out of NFS and mount sdmmc and do a
> 
> $ echo -n mem > /sys/power/state
> 
> However, If i boot out of SDMMC (rootfs on sdmmc). I am not able to
> bring it out of suspend.
> The kernel hangs.
> 
> I get the message:
> # echo -n mem > /sys/power/state
> PM: Syncing filesystems ... done.
> Freezing user space processes ... (elapsed 0.00 seconds) done.
> Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done.
> mmc0: card e624 removed

seems like mmc driver problem...  

(You may still have some fun if you fix that one with mmc
maintainers... because 'is it still same card' is difficult question,
but...)

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html