linux-kernel - Re: [PATCH] Revert "backlight: pwm: Handle EPROBE

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Message-ID: <87bncjemdk.fsf@belgarion.home>
Date:	Wed, 30 Sep 2015 21:29:59 +0200
From:	Robert Jarzmik <robert.jarzmik@...e.fr>
To:	Thierry Reding <thierry.reding@...il.com>,
	Nicolas Ferre <nicolas.ferre@...el.com>
Cc:	Jingoo Han <jingoohan1@...il.com>,
	Lee Jones <lee.jones@...aro.org>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>,
	linux-pwm@...r.kernel.org, linux-fbdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Revert "backlight: pwm: Handle EPROBE_DEFER while requesting the PWM"

Robert Jarzmik <robert.jarzmik@...e.fr> writes:

> This reverts commit 68feaca0b13e453aa14ee064c1736202b48b342f.
> This commit breaks legacy platforms, for which :
>  (a) no pwm table is added (legacy platforms)
>  (b) in this case, in pwm_get(), pmw_lookup_list is empty, and therefore
>      chosen == NULL, and therefore pwm_get() returns NULL, and pwm_get()
>      returns -EPROBE_DEFER
>  (c) as a consequence, this code is unreachable in pwm_bl.c :
>      if (IS_ERR(pb->pwm)) {
> 	ret = PTR_ERR(pb->pwm);
>  	dev_info(&pdev->dev, "%s:%d(): %d\n", __func__, __LINE__, ret);
>  	if (ret == -EPROBE_DEFER)
>  		goto err_alloc;
>
>  	dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
>  	pb->legacy = true;
>  	pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
>
> As this code is unreachable, all legacy platforms relying on pwm_id are
> broken, amongst which pxa have been tested as broken.
>
> Signed-off-by: Robert Jarzmik <robert.jarzmik@...e.fr>
Thierry, would you have a look please ?
As I said before, all legacy platform relying on pwm_id are broken. I'd like to
be sure this lands in the next -rc series.

Cheers.

--
Robert
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