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From: Archit Taneja <a0393947@ti.com>
To: "Shilimkar, Santosh" <santosh.shilimkar@ti.com>
Cc: "Cousson, Benoit" <b-cousson@ti.com>,
	Tomi Valkeinen <tomi.valkeinen@ti.com>,
	Paul Walmsley <paul@pwsan.com>,
	linux-omap <linux-omap@vger.kernel.org>,
	Kevin Hilman <khilman@ti.com>
Subject: Re: OMAP4 errata i740
Date: Fri, 30 Mar 2012 16:47:16 +0530	[thread overview]
Message-ID: <4F75963C.2000508@ti.com> (raw)
In-Reply-To: <CAMQu2gzXoqwdmd6xMs+Rp6TQDJtjQf+ydtRb3AL6+APnmfHzHA@mail.gmail.com>

On Friday 30 March 2012 04:34 PM, Shilimkar, Santosh wrote:
> On Fri, Mar 30, 2012 at 4:26 PM, Archit Taneja<a0393947@ti.com>  wrote:
>> On Friday 30 March 2012 03:59 PM, Santosh Shilimkar wrote:
>>>
>>> On Friday 30 March 2012 03:53 PM, Cousson, Benoit wrote:
>>>>
>>>> On 3/30/2012 10:44 AM, Santosh Shilimkar wrote:
>>>>>
>>>>> On Friday 30 March 2012 02:04 PM, Archit Taneja wrote:
>>>>>>
>>>>>> On Friday 30 March 2012 02:01 PM, Santosh Shilimkar wrote:
>>>>>>>
>>>>>>> + Kevin
>>>>>>>
>>>>>>> On Friday 30 March 2012 01:56 PM, Tomi Valkeinen wrote:
>>>>>>>>
>>>>>>>> On Fri, 2012-03-30 at 13:51 +0530, Shilimkar, Santosh wrote:
>>>>>>>>>
>>>>>>>>> On Fri, Mar 30, 2012 at 1:37 PM, Tomi
>>>>>>>>> Valkeinen<tomi.valkeinen@ti.com>      wrote:
>>>>>>>>
>>
> [...]
>
>>
>> I had a general PRCM question regarding this. If an initiator is disabled
>> (i.e, clocks are OFF and Power state is OFF), then would the PRCM even care
>> to look at the IdleAck/Mstandby signal of that initiator? Or in other words,
>> look at what the initiator had programmed in it's SYSCONFIG register. If it
>> does consider them, it seems like that's bad HW design!
>>
> If a PD 9powerdomain) is already in OFF state, that means all the initiators in
> that PD already has standby asserted. The modules in that
> PD also have transitioned.

Ah, so if DSS was configured as Nostandby, and if we try to disable DSS, 
it would never transition to OFF, and hence never get disabled 
correctly, hence giving trouble to PRCM.

So just before disabling DSS, we would need to put it to Force standby, 
and then try to cut the clocks and change the power state. Is this 
correct? If so, then it's equally messy as the suggested workaround :)

Archit

>
> So PRCM won't poke that PD initiators/modules because it has
> already have a green signal for power transitions. At least that is
> what my understanding from the OMAP PRCM specs.
>
> Regards
> Santosh
>


  reply	other threads:[~2012-03-30 11:17 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-30  8:07 OMAP4 errata i740 Tomi Valkeinen
2012-03-30  8:21 ` Shilimkar, Santosh
2012-03-30  8:26   ` Tomi Valkeinen
2012-03-30  8:31     ` Santosh Shilimkar
2012-03-30  8:34       ` Archit Taneja
2012-03-30  8:44         ` Santosh Shilimkar
2012-03-30 10:23           ` Cousson, Benoit
2012-03-30 10:29             ` Santosh Shilimkar
2012-03-30 10:56               ` Archit Taneja
2012-03-30 11:04                 ` Shilimkar, Santosh
2012-03-30 11:17                   ` Archit Taneja [this message]
2012-03-30 11:20                     ` Shilimkar, Santosh
2012-03-30 11:59                       ` Tomi Valkeinen
2012-03-30 12:02                         ` Cousson, Benoit
2012-03-30 12:06                           ` Tomi Valkeinen
2012-03-30 12:00                       ` Cousson, Benoit
2012-03-30 12:24                         ` Santosh Shilimkar
2012-03-30 10:08     ` Cousson, Benoit

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