linux-kernel - [PATCH v1 03/28] leds: el15203000: Give better margin for usleep

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20210510095045.3299382-4-andy.shevchenko@gmail.com>
Date:   Mon, 10 May 2021 12:50:20 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Pavel Machek <pavel@....cz>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Amireddy Mallikarjuna reddy 
        <mallikarjunax.reddy@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Marek Behún <marek.behun@....cz>,
        Abanoub Sameh <abanoubsameh8@...il.com>,
        Dan Murphy <dmurphy@...com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Andy Shevchenko <andy.shevchenko@...il.com>
Subject: [PATCH v1 03/28] leds: el15203000: Give better margin for usleep_range()

1 microsecond with 20 millisecond parameter is too low margin for
usleep_range(). Give 100 to make scheduler happier.

While at it, fix indentation in cases where EL_FW_DELAY_USEC is in use.
In the loop, move it to the end to avoid a conditional.

Signed-off-by: Andy Shevchenko <andy.shevchenko@...il.com>
---
 drivers/leds/leds-el15203000.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/leds/leds-el15203000.c b/drivers/leds/leds-el15203000.c
index 6ca47f2a2004..912451db05e6 100644
--- a/drivers/leds/leds-el15203000.c
+++ b/drivers/leds/leds-el15203000.c
@@ -95,27 +95,22 @@ static int el15203000_cmd(struct el15203000_led *led, u8 brightness)
 
 	/* to avoid SPI mistiming with firmware we should wait some time */
 	if (time_after(led->priv->delay, jiffies)) {
-		dev_dbg(led->priv->dev, "Wait %luus to sync",
-			EL_FW_DELAY_USEC);
+		dev_dbg(led->priv->dev, "Wait %luus to sync", EL_FW_DELAY_USEC);
 
-		usleep_range(EL_FW_DELAY_USEC,
-			     EL_FW_DELAY_USEC + 1);
+		usleep_range(EL_FW_DELAY_USEC, EL_FW_DELAY_USEC + 100);
 	}
 
 	cmd[0] = led->reg;
 	cmd[1] = brightness;
 
 	for (i = 0; i < ARRAY_SIZE(cmd); i++) {
-		if (i)
-			usleep_range(EL_FW_DELAY_USEC,
-				     EL_FW_DELAY_USEC + 1);
-
 		ret = spi_write(led->priv->spi, &cmd[i], sizeof(cmd[i]));
 		if (ret) {
 			dev_err(led->priv->dev,
 				"spi_write() error %d", ret);
 			break;
 		}
+		usleep_range(EL_FW_DELAY_USEC, EL_FW_DELAY_USEC + 100);
 	}
 
 	led->priv->delay = jiffies + usecs_to_jiffies(EL_FW_DELAY_USEC);
@@ -313,8 +308,7 @@ static int el15203000_probe(struct spi_device *spi)
 	priv->count	= count;
 	priv->dev	= &spi->dev;
 	priv->spi	= spi;
-	priv->delay	= jiffies -
-			  usecs_to_jiffies(EL_FW_DELAY_USEC);
+	priv->delay	= jiffies - usecs_to_jiffies(EL_FW_DELAY_USEC);
 
 	spi_set_drvdata(spi, priv);
 
-- 
2.31.1