linux-kernel - Re: [PATCH AUTOSEL 4.14 05/15] regulator: pwm: Fix machine constraints application

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]

Message-ID: <20200915075508.jddoubwnptjcqtru@axis.com>
Date:   Tue, 15 Sep 2020 09:55:08 +0200
From:   Vincent Whitchurch <vincent.whitchurch@...s.com>
To:     Sasha Levin <sashal@...nel.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Mark Brown <broonie@...nel.org>
Subject: Re: [PATCH AUTOSEL 4.14 05/15] regulator: pwm: Fix machine
 constraints application

On Mon, Sep 14, 2020 at 03:05:16PM +0200, Sasha Levin wrote:
> From: Vincent Whitchurch <vincent.whitchurch@...s.com>
> 
> [ Upstream commit 59ae97a7a9e1499c2070e29841d1c4be4ae2994a ]
> 
> If the zero duty cycle doesn't correspond to any voltage in the voltage
> table, the PWM regulator returns an -EINVAL from get_voltage_sel() which
> results in the core erroring out with a "failed to get the current
> voltage" and ending up not applying the machine constraints.
> 
> Instead, return -ENOTRECOVERABLE which makes the core set the voltage
> since it's at an unknown value.

For this patch to work it needs 84b3a7c9c6befe5ab4d49070fe7 ("regulator:
core: Allow for regulators that can't be read at bootup") which was
merged in v4.18.  Without that this patch is not going to have any
effect so it probably shouldn't be backported to older kernels.