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Message-ID: <6c622fd7-d79b-b7f2-50ee-00a0ec95a11b@leemhuis.info>
Date:   Tue, 20 Jun 2023 16:24:31 +0200
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Subject: Re: PWM regression causing failures with the pwm-atmel driver
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To:     Peter Rosin <peda@axentia.se>, LKML <linux-kernel@vger.kernel.org>,
        =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <u.kleine-koenig@pengutronix.de>,
        linux-pwm@vger.kernel.org
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Conor Dooley <conor.dooley@microchip.com>,
        Claudiu Beznea <claudiu.beznea@microchip.com>
References: <7e2cfb55-e39f-2e5c-7f43-e1d275428bb5@axentia.se>
From:   Thorsten Leemhuis <regressions@leemhuis.info>
In-Reply-To: <7e2cfb55-e39f-2e5c-7f43-e1d275428bb5@axentia.se>
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On 22.05.23 17:19, Peter Rosin wrote:
>
> I have a device with a "sound card" that has an amplifier that needs
> an extra boost when high amplification is requested. This extra
> boost is controlled with a pwm-regulator.
> 
> As of commit c73a3107624d ("pwm: Handle .get_state() failures") this
> device no longer works. I have tracked the problem to an unfortunate
> interaction between the underlying PWM driver and the PWM core.
> [...]>
> Approach 1. will maybe clobber the saved pwm->state such that
> it no longer works to get the period/duty_cycle if/when the
> PWM is disabled? Maybe only for some corner case? But that might
> be a significant corner case?
> 
> Approach 2. will maybe mess up some unrelated functionality?
> 
> Approach 3. is ugly, intrusive and is in all likelihood
> incomplete. It also needs a rebase from the culprit commit.
> 
> #regzbot introduced c73a3107624d

What happened to this? There was quite a bit of discussion, but then
nothing happened anymore.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.

#regzbot poke