From: Shuah Khan <shuah.kh@samsung.com>
To: "david-b@pacbell.net" <david-b@pacbell.net>,
        "dbrownell@users.sourceforge.net" <dbrownell@users.sourceforge.net>,
        "rjw@sisk.pl" <rjw@sisk.pl>, "pavel@ucw.cz" <pavel@ucw.cz>,
        "stern@rowland.harvard.edu" <stern@rowland.harvard.edu>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: sl811h_suspend() and PM_EVENT_PRETHAW state handling
Thread-topic: sl811h_suspend() and PM_EVENT_PRETHAW state handling
Thread-index: Ac6SyFcWUhE6FBeWT/iSf5cAZjp8ng==
Date: Tue, 06 Aug 2013 17:14:00 +0000
Message-id: <B8EFE96D1287C24090BAD9D858E15E6175A08F@sisaex02sj>
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sl811h_suspend() seems to be the odd routine in the way it handles the 
PM_EVENT_PRETHAW state. It treats it same as PM_EVENT_SUSPEND and 
PM_EVENT_HIBERNATE. All other uses I could find treat it same as 
PM_EVENT_FREEZE and PM_EVENT_QUIESCE. Makes sense since PM_EVENT_PRETHAW 
is PM_EVENT_QUIESCE.

#define PM_EVENT_PRETHAW PM_EVENT_QUIESCE

Reference: Commit 185849991d592497e43bcd264c6152af1261ffe2 introduced 
PM_EVENT_PRETHAW state to sl811h_suspend().

Couple of questions?

- Why does sl811h_suspend() treat PM_EVENT_PRETHAW different from 
PM_EVENT_FREEZE?

There is no problem with this code as such, since state is passed in. 
However, this usage conflicts with the rest of the usages and the way 
pm_op() routine maps PM_EVENT_PRETHAW/PM_EVENT_QUIESCE to freeze() pm_ops.

         case PM_EVENT_FREEZE:
         case PM_EVENT_QUIESCE:
                 return ops->freeze;

Assuming the handling PM_EVENT_PRETHAW is correct in this routine, what 
would be the right mapping for this legacy handling to dev_pm_ops?

-- Shuah

Shuah Khan, Linux Kernel Developer - Open Source Group Samsung Research 
America (Silicon Valley) shuah.kh@samsung.com | (970) 672-0658
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