Attachment 144914 Details for Bug 96571 – [PATCH] pwm: Fallback to the static lookup-list when acpi_pwm_get fails

[patch] [PATCH] pwm: Fallback to the static lookup-list when acpi_pwm_get fails

0001-pwm-Fallback-to-the-static-lookup-list-when-acpi_pwm.patch (text/plain), 2.00 KB, created by Hans de Goede on 2019-07-30 15:56:30 UTC

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Creator: Hans de Goede

Created: 2019-07-30 15:56:30 UTC

Size: 2.00 KB

patch

obsolete

>From aa88e2e75ec9536a137cf8c14919d91c55d8a0dc Mon Sep 17 00:00:00 2001
>From: Hans de Goede <hdegoede@redhat.com>
>Date: Tue, 30 Jul 2019 17:39:28 +0200
>Subject: [PATCH] pwm: Fallback to the static lookup-list when acpi_pwm_get
> fails
>
>Commit 4a6ef8e37c4d ("pwm: Add support referencing PWMs from ACPI")
>made pwm_get unconditionally return the acpi_pwm_get return value if
>the device passed to pwm_get has an ACPI fwnode.
>
>But even if the passed in device has an ACPI fwnode, it does not
>necessarily have the necessary ACPI package defining its pwm bindings,
>especially since the binding / API of this ACPI package has only been
>introduced very recently.
>
>Up until now X86/ACPI devices which use a separate pwm controller for
>controlling their LCD screen's backlight brightness have been relying
>on the static lookup-list to get their pwm.
>
>pwm_get unconditionally returning the acpi_pwm_get return value breaks
>this, breaking backlight control on these devices.
>
>This commit fixes this by making pwm_get fall back to the static
>lookup-list if acpi_pwm_get returns -ENOENT.
>
>BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=96571
>Reported-by: youling257@gmail.com
>Fixes: 4a6ef8e37c4d ("pwm: Add support referencing PWMs from ACPI")
>Cc: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
>Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>---
> drivers/pwm/core.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
>index c3ab07ab31a9..8edfac17364e 100644
>--- a/drivers/pwm/core.c
>+++ b/drivers/pwm/core.c
>@@ -882,8 +882,11 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
> 		return of_pwm_get(dev, dev->of_node, con_id);
> 
> 	/* then lookup via ACPI */
>-	if (dev && is_acpi_node(dev->fwnode))
>-		return acpi_pwm_get(dev->fwnode);
>+	if (dev && is_acpi_node(dev->fwnode)) {
>+		pwm = acpi_pwm_get(dev->fwnode);
>+		if (!IS_ERR(pwm) || PTR_ERR(pwm) != -ENOENT)
>+			return pwm;
>+	}
> 
> 	/*
> 	 * We look up the provider in the static table typically provided by
>-- 
>2.21.0
>

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Attachments on bug 96571: 124781 | 125013 | 125015 | 125017 | 125034 | 138976 | 144914

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