linux-kernel - Re: [PATCH] spi: Gracefully handle power supplies with disabled PM

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Message-ID: <20180917162732.GA2471@sirena.org.uk>
Date:   Mon, 17 Sep 2018 17:27:32 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Lubomir Rintel <lkundrak@...sk>
Cc:     linux-kernel@...r.kernel.org, linux-spi@...r.kernel.org
Subject: Re: [PATCH] spi: Gracefully handle power supplies with disabled PM

On Mon, Sep 17, 2018 at 02:10:41PM +0200, Lubomir Rintel wrote:
> This allows use of SPI when power management is disables, such as on
> early boot;
> 
> See also: commit 31eb74318054 ("PM / runtime: Fix handling of suppliers
> with disabled runtime PM")

>  	if (!was_busy && ctlr->auto_runtime_pm) {
>  		ret = pm_runtime_get_sync(ctlr->dev.parent);
> -		if (ret < 0) {
> +		if (ret < 0 && ret != -EACCES) {

No, this is not at all clever.  If the device uses runtime PM and
doesn't get resumed then there is every likelyhood that the device won't
even be clocked.  If users want to disable power management it's going
to need rather more work than just setting a flag.

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