linux-kernel - Re: [PATCH] regulator: twl: Enable regulators over the powerbus as well

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 25 Mar 2016 19:22:45 +0200
From:	Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>
To:	Mark Brown <broonie@...nel.org>
Cc:	Sebastian Reichel <sre@...nel.org>, tony@...mide.com,
	lgirdwood@...il.com, linux-omap@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] regulator: twl: Enable regulators over the powerbus as
 well

On 25.03.2016 19:05, Mark Brown wrote:
> On Fri, Mar 25, 2016 at 06:50:18PM +0200, Ivaylo Dimitrov wrote:
>> On 25.03.2016 18:19, Mark Brown wrote:
>
>>> What makes you claim that this is a bug in the framework?  Does anything
>>> in the machine configuration say that changing the modes is allowed?
>
>> My understanding is that regulator core have to make sure an enabled
>> regulator to be in REGULATOR_STATUS_NORMAL. Now it enables the regulator,
>
> No, absolutely not.  Modes are completely orthogonal to enabling and
> disabling the regulator - modes reflect an efficiency/accuracy tradeoff
> in the regulation, they are nothing to do with the regulator being
> enabled.  Setting a mode should not affect the regulator enable state
> and enabling the regulator should not affect the mode.
>
>> It might be that I am not getting the logic behind.
>
> Yes, that seems to be the case.
>

Fair enough.

Now, what am I supposed to do to the fix the problem. Will try to 
explain it in more details:

On Nokia N900 regulators are left in the mode last set by the bootloader 
or by the stock kernel, depends on whether it is power-on or reboot from 
stock kernel to mainline. That leads to problem with devices connected 
to vmmc2 regulator - when the device is rebooted from stock kernel vmmc2 
is left in "sleep" mode (REGULATOR_STATUS_STANDBY in terms of regulator 
framework) and as noone in mainline kernel switches vmmc2 regulator to 
normal (REGULATOR_STATUS_NORMAL) mode, devices supplied by it does not 
get enough power to operate normally.