Re: [PATCH 12/13] DSPBRIDGE: fix resuming problem with dsp hibernation

[Ameya Palande <ameya.palande@nokia.com>]

Hi Fernando,

ext Guzman Lugo, Fernando wrote:
> 
> Hi,
> 
>> -----Original Message-----
>> From: Ameya Palande [mailto:ameya.palande@nokia.com]
>> Sent: Wednesday, July 15, 2009 9:57 AM
>> To: linux-omap@vger.kernel.org
>> Cc: Ramirez Luna, Omar; Guzman Lugo, Fernando; Menon, Nishanth;
>> hiroshi.doyu@nokia.com
>> Subject: [PATCH 12/13] DSPBRIDGE: fix resuming problem with dsp
>> hibernation
>>
>> From: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>
>>
>> The constraints(opp >= 2) should be set whenever returning from DSP
>> hibernation.
>>
>> This fixes the problem at the following steps:
>> 1) wait DSP hibernate
>> 2) echo mem > /sys/power/state
>> 3) type key to wakeup
>>
> 
> The patch looks good, you are removing the check for OPP1 because it is suppose
> that if the DSP is in Hibernation we have a DSP constrain in OPP1,
> so I think the "if" is always true. However I don't see the issue the mention
> could you please tell me what was the problem you were seeing?

While waking up DSP if VDD1 OPP is greater that 1 then without this patch,
constraint won't be set. This results in a case where PM layer later decides to
switch to OPP1 while DSP is active, which results in a crash. To avoid this we
are setting VDD1 to OPP2 unconditionally while waking up from hibernation :)

Cheers,
Ameya.