Re: PM with rootfs on mmc?

Sriram V
2008-12-31T15:32:06Z

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
>
>
>