Re: MFD USB host: prevents CORE retention in idle

[Kevin Hilman <khilman@ti.com>]

"Munegowda, Keshava" <keshava_mgowda@ti.com> writes:

> On Fri, Jun 15, 2012 at 7:17 PM, Jean Pihet <jean.pihet@newoldbits.com> wrote:
>> Hi Keshava,
>>
>> On Fri, Jun 15, 2012 at 2:04 PM, Munegowda, Keshava
>> <keshava_mgowda@ti.com> wrote:
>>> On Tue, Jun 12, 2012 at 6:28 PM, Munegowda, Keshava
>>> <keshava_mgowda@ti.com> wrote:
>>>> hi kevin
>>>>         now I am using initramfs with kernel linux3.5.rc1,
>>>> but the retention is not working in 3430 sdp.  I am seeing the following
>>>> error followed by a crash
>>>>
>>>>
>>>> echo mem > /sys/power/state
>>>> [   35.609252] PM: Syncing filesystems ... done.
>>>> [   35.614654] PM: Preparing system for mem sleep
>>>> [   35.658630] Freezing user space processes ... (elapsed 0.01 seconds)
>>>> done.
>>>> [   35.689727] Freezing remaining freezable tasks ... (elapsed 0.02 seconds)
>>>> done.
>>>> [   35.697692] PM: Entering mem sleep
>>>> [   35.722442] usb usb1: usb auto-resume
>>>> [   35.726409] ehci-omap ehci-omap.0: resume root hub
>>>> [   35.775451] hub 1-0:1.0: hub_resume
>>>> [   35.779846] hub 1-0:1.0: hub_suspend
>>>> [   35.784240] usb usb1: bus suspend, wakeup 0
>>>> [   35.788665] ehci-omap ehci-omap.0: suspend root hub
>>>> [   35.805786] PM: suspend of devices complete after 99.304 msecs
>>>> [   35.816497] PM: late suspend of devices complete after 4.364 msecs
>>>> [   35.831573] PM: noirq suspend of devices complete after 8.331 msecs
>>>> [   35.838500] Disabling non-boot CPUs ...
>>>> [   36.312164] Powerdomain (core_pwrdm) didn't enter target state 1
>>>> [   36.318481] Could not enter target state in pm_suspend
>>>> [   36.324859] Unable to handle kernel NULL pointer dereference at virtual
>>>> address 00000018
>>>> [   36.333557] pgd = c6280000
>>>> [   36.336639] [00000018] *pgd=85c8f831, *pte=00000000, *ppte=00000000
>>>> [   36.343414] Internal error: Oops: 17 [#1] SMP ARM
>>>> [   36.348388] Modules linked in:
>>>> [   36.351623] CPU: 0    Tainted: G        W     (3.5.0-rc1 #1)
>>>> [   36.357574] PC is at _od_resume_noirq+0x14/0x58
>>>> [   36.362365] LR is at dpm_run_callback+0x2c/0x74
>>
>> You need the fix from
>> https://gitorious.org/linux-omap-dss2/linux/commit/9e0ca55fa5d9ff012964a7c7cef8af1b814b2fdb
>>
>> Hope this helps!
>>
>> Regards,
>> Jean
>
> thanks Jean
>     I used this patch; this solved the crash issue, but suspend/resume
> is still failing.

Failing in what way?  Did you debug any further?

It may be failing because of problems with the USB host driver, which is
what I'm needing you to debug.

I'm convinced now that these USB host PM changes were not very well
tested at all as they seem to be causing a variety of different problems
on my boards: faults during boot, preventing CORE idle retention,
hanging suspend/resume.

Anyways...

To get current l-o master to succesfully suspend/resume, you need 3 things:

1) the DSS fixes that Jean mentioned above (these are merged in
   v3.5-rc3, but not yet into l-o master)
2) disable USB host: set CONFIG_MFD_OMAP_USB_HOST=n
3) for for 32k timer which is also preventing CORE retention
   http://marc.info/?l=linux-omap&m=134000053229888&w=2

With that setup on top of current l-o master, suspend/resume is working
for me on several OMAP3/4 platforms.

Kevin
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