Linux-LEDs Archive on lore.kernel.org
 help / color / Atom feed
From: Kai-Heng Feng <kai.heng.feng@canonical.com>
To: jacek.anaszewski@gmail.com, pavel@ucw.cz
Cc: anthony.wong@canonical.com,
	Kai-Heng Feng <kai.heng.feng@canonical.com>,
	Dan Murphy <dmurphy@ti.com>,
	linux-leds@vger.kernel.org (open list:LED SUBSYSTEM),
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] leds: core: Use blocking op for system suspend
Date: Wed,  1 Jul 2020 17:35:40 +0800
Message-ID: <20200701093541.14191-1-kai.heng.feng@canonical.com> (raw)

Sometimes LED won't be turned off by LED_CORE_SUSPENDRESUME flag upon
system suspend.

led_set_brightness_nopm() uses schedule_work() to set LED brightness.
However, there's no guarantee that the scheduled work gets executed
because no one calls flush_scheduled_work().

As flush_scheduled_work() may affect other drivers' suspend routines,
take a more contained approach which uses blocking op to make sure the
LED gets turned off.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
---
 drivers/leds/led-core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/leds/led-core.c b/drivers/leds/led-core.c
index f1f718dbe0f8..9a5bfcd7a704 100644
--- a/drivers/leds/led-core.c
+++ b/drivers/leds/led-core.c
@@ -269,6 +269,11 @@ EXPORT_SYMBOL_GPL(led_set_brightness);
 void led_set_brightness_nopm(struct led_classdev *led_cdev,
 			      enum led_brightness value)
 {
+
+	if (led_cdev->flags & LED_SUSPENDED &&
+	    !__led_set_brightness_blocking(led_cdev, value))
+		return;
+
 	/* Use brightness_set op if available, it is guaranteed not to sleep */
 	if (!__led_set_brightness(led_cdev, value))
 		return;
-- 
2.17.1


             reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-01  9:35 Kai-Heng Feng [this message]
2020-07-01 21:28 ` Jacek Anaszewski
2020-07-02  5:20   ` Kai-Heng Feng

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200701093541.14191-1-kai.heng.feng@canonical.com \
    --to=kai.heng.feng@canonical.com \
    --cc=anthony.wong@canonical.com \
    --cc=dmurphy@ti.com \
    --cc=jacek.anaszewski@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-leds@vger.kernel.org \
    --cc=pavel@ucw.cz \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-LEDs Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-leds/0 linux-leds/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-leds linux-leds/ https://lore.kernel.org/linux-leds \
		linux-leds@vger.kernel.org
	public-inbox-index linux-leds

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-leds


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git