linux-kernel - Re: [tpmdd-devel] [PATCH 3/4] tpm: Convert tpm_tis driver to use dev_pm_ops from legacy pm

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Message-id: <B8EFE96D1287C24090BAD9D858E15E61738C1B@sisaex02sj>
Date:	Thu, 11 Jul 2013 01:30:43 +0000
From:	Shuah Khan <shuah.kh@...sung.com>
To:	Peter Hüwe <PeterHuewe@....de>
Cc:	"tpmdd-devel@...ts.sourceforge.net" 
	<tpmdd-devel@...ts.sourceforge.net>,
	"rafael.j.wysocki@...el.com" <rafael.j.wysocki@...el.com>,
	"bhelgaas@...gle.com" <bhelgaas@...gle.com>,
	"a.zummo@...ertech.it" <a.zummo@...ertech.it>,
	"key@...ux.vnet.ibm.com" <key@...ux.vnet.ibm.com>,
	"mail@...jiv.net" <mail@...jiv.net>,
	"tpmdd@...horst.net" <tpmdd@...horst.net>,
	"tpmdd@...rix.com" <tpmdd@...rix.com>,
	"matthew.garrett@...ula.com" <matthew.garrett@...ula.com>,
	"rtc-linux@...glegroups.com" <rtc-linux@...glegroups.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"platform-driver-x86@...r.kernel.org" 
	<platform-driver-x86@...r.kernel.org>,
	"shuahkhan@...il.com" <shuahkhan@...il.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Shuah Khan <shuah.kh@...sung.com>
Subject: Re: [tpmdd-devel] [PATCH 3/4] tpm: Convert tpm_tis driver to use
 dev_pm_ops from legacy pm_ops

Hi Peter,

On 07/10/2013 05:30 PM, Peter Hüwe wrote:

>>
>> tpm_tis_resume() is defined originally in CONFIG_PM_SLEEP scope. I can
>> make the change to have tpm_tis_resume() not be in CONFIG_PM_SLEEP scope
>> and remove this CONFIG_PM_SLEEP when defining .pm.
>> That does make sense looking at tpm_pm_suspend() and tpm_pm_resume() which
>> are defined ithout CONFIG_PM_SLEEP scope. Sounds like the right approach?
>> I will redo the patch and send v2.
>
> Hmm,
> at first I thought that would be a good idea, however scrolling to the git
> history I found:
>
> commit 07368d32f1a67e797def08cf2ee3ea1647b204b6
> Author: Rafael J. Wysocki <rjw@...k.pl>
> Date:   Thu Aug 9 23:00:35 2012 +0200
>
>      tpm_tis / PM: Fix unused function warning for CONFIG_PM_SLEEP
>
>      According to a compiler warning, the tpm_tis_resume() function is not
>      used for CONFIG_PM_SLEEP unset, so add a #ifdef to prevent it from
>      being built in that case.
>
>      Signed-off-by: Rafael J. Wysocki <rjw@...k.pl>
>
> So removing it there would effectively revert the patch and re-enable the
> warning.
>
>
>
>> I find that the use of CONFIG_PM, CONFIG_PM_SLEEP, and CONFIG_PM_RUNTIME
>> are not very consistent. :)
> Yes.
>
> Maybe the better idea is to add the correct CONFIG_PM ifdefs for all code
> paths related to PM.
> Or leave the CONFIG_PM for tpm_tis_resume as it is.
>
>

For now, leaving tpm_tis_resume() is better to keep this change simpler. 
I am seeing this type of inconsistency in several drivers as I am going 
around making changes to convert from legacy pm_ops to dev_pm_ops. At 
some point, it might be worth while looking at the usage of these 
defines and set some clear guidelines.

-- Shuah

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