linux-kernel - Re: [PATCH 2/2] media: pwm-ir-tx: trigger edges from hrtimer interrupt context

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: <20231002085902.63b6cpql5tgwdhbw@pengutronix.de>
Date:   Mon, 2 Oct 2023 10:59:02 +0200
From:   Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To:     Sean Young <sean@...s.org>
Cc:     Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pwm@...r.kernel.org
Subject: Re: [PATCH 2/2] media: pwm-ir-tx: trigger edges from hrtimer
 interrupt context

Hello Sean,

On Mon, Oct 02, 2023 at 09:20:20AM +0100, Sean Young wrote:
> Having said that, the extra call to pwm_apply_state() may have benefits,
> see this comment in the pwm-sifive driver:
> 
>  * - When changing both duty cycle and period, we cannot prevent in
>  *   software that the output might produce a period with mixed
>  *   settings (new period length and old duty cycle).

You don't gain anything here I think. Disabling a PWM might also result
in a constant active level. If you want to prevent this, your best bet
is to never disable the PWM.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)