Re: What is missing from musb - linux-omap merge?

[Kevin Hilman <khilman@ti.com>]

Jarkko Nikula <jhnikula@gmail.com> writes:

> On Wed, 6 Apr 2011 16:34:40 +0300
> Felipe Balbi <balbi@ti.com> wrote:
>
>> Hi,
>> 
>> On Wed, Apr 06, 2011 at 04:23:34PM +0300, Jarkko Nikula wrote:
>> > Hi
>> > 
>> > I've been trying to hunt why the OMAP3 retention on Nokia N900 went
>> > broken in 2.6.39-rc and reason is somewhere around musb code merge with
>> > linux-omap code or vise versa.
>> > 
>> > I bisected this into:
>> 
>> I guess it's the missing Hema's patch which should be queued already.
>> Here it is:
>> 
>> commit 84cebd52a4b5d590af476869dc5b786fe567c095
>> Author: Hema HK <hemahk@ti.com>
>> Date:   Thu Mar 17 16:11:58 2011 +0530
>> 
>>     usb: musb: Fix for merge issue
>>     
> Yeah, that was missing from the commits I was testing but it was in
> where I started bisecting and where I noticed the retention issue so
> this don't fix it.
>
>> you might also need the one below:
>> 
>> commit ee262c660a855864efa78181cf7b7095b6416098
>> Author: Hema HK <hemahk@ti.com>
>> Date:   Tue Mar 22 16:02:12 2011 +0530
>> 
>>     usb: musb: Fix the crash issue during reboot
>>     
> Applies fine to 2.6.39-rc2 but still doesn't fix the retention issue.

Without actually trying this myself, what is likely affecting retention
is probably a missing (or failed) reset of the MUSB module.

Retention was also broken on several platforms before the MUSB cleanup &
hwmod conversion because the reset happens during hwmod init.  Because
most bootloaders are using MUSB, they often leave it in a state that
prevents idle (and thus retention), so a hwmod reset is the most
reliable way go get the IP into a known state.

Kevin