Re: [PATCH] OMAP: USB : Fix the EHCI enumeration and core retention issue

From: Kevin Hilman <khilman@ti.com>
To: "Munegowda, Keshava" <keshava_mgowda@ti.com>
Cc: linux-omap@vger.kernel.org, linux-usb@vger.kernel.org,
	balbi@ti.com, sameo@linux.intel.com, notasas@gmail.com
Subject: Re: [PATCH] OMAP: USB : Fix the EHCI enumeration and core retention issue
Date: Fri, 22 Jun 2012 11:49:22 -0700	[thread overview]
Message-ID: <87lijfkwr1.fsf@ti.com> (raw)
In-Reply-To: <CAP05o4+6LxwdwCUQF_0b6dCQ9JQarNeUBzO=qgdUgnreMtDeMg@mail.gmail.com> (Keshava Munegowda's message of "Fri, 22 Jun 2012 20:13:49 +0530")

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

> On Fri, Jun 22, 2012 at 7:41 PM, Kevin Hilman <khilman@ti.com> wrote:
>> "Munegowda, Keshava" <keshava_mgowda@ti.com> writes:
>>
>> [...]
>>
>>>>>
>>>>> hi kevin
>>>>>
>>>>> here is pm count log on beagle XM with the above patch:
>>>>
>>>> What are you meaning to show by this log?
>>>>
>>>> This dump shows that neither PER or CORE are hitting retention in idle.
>>>> Which sounds to me like you have not enabled UART runtime suspend:
>>>>
>>>> echo 3000 > /sys/devices/platform/omap_uart.0/power/autosuspend_delay_ms
>>>> echo 3000 > /sys/devices/platform/omap_uart.1/power/autosuspend_delay_ms
>>>> echo 3000 > /sys/devices/platform/omap_uart.2/power/autosuspend_delay_ms
>>>> echo 3000 > /sys/devices/platform/omap_uart.3/power/autosuspend_delay_ms
>>>>
>>>> My test with your patch shows that it fixes the oops during boot, and
>>>> doesn't hang during suspend, but that USB host is still preventing CORE
>>>> retention during idle (after UART runtime suspend is enabled.)
>>>>
>>>> This happens on 3530/Overo, 3630/Beagle-xM and 3730/Overo
>>>>
>>>> Setting CONFIG_MFD_OMAP_USB_HOST=n allows CORE to hit retention again.
>>>>
>>>> Kevin
>>>
>>>
>>>
>>> Hi kevin
>>>        It woks. only the log was wrong. I was using no_console_suspend
>>> in boot args.
>>> i removed it. now I can see the core retention hits with USB host in Beagle XM.
>>> below is the log:
>>>
>>
>> You are not reading what I write.
>>
>> To repeat: your patch fixes the oops during boot, and the suspend hang
>> and now I see CORE hit retention in *suspend*.
>
> thanks !
>
>>
>> However,  CORE does still not hit retention during *idle*.
>
> here is the problem.
>
> usb host retention in idle is not supported till now.
> in current code, usb host cuts clock only in driver suspend not in bus
> suspend ( auto suspend).
>
> usb host driver need to use the  io daisy chain framework through io wakeup.
> I will post the patches once ehci remote wakeup features stabilized in
> omap3, omap4 and omap5 too.

Then I suggest you revert the changes that introduced this PM support
until it is fully working.  

The current form of the code prevents retention for the *whole* SoC
during idle because it prevents CORE retention.

The PM support for this driver was clearly not fully tested and should
be reverted until it can be tested and fully validated.

Please revert the PM changes for v3.5-rc.

Kevin
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