Commit cd4c1b41 authored by Nicholas Mc Guire's avatar Nicholas Mc Guire Committed by Dmitry Torokhov
Browse files

Input: cyapa - use time based retry loop 



Using counter based retry loops for peripherals results in the delay
being significantly overrun during high-load situations where delay
functions tend to be vary imprecise and overrun there timeouts. So
condition the termination on the actual condition of 2s for the
re-calibration to have been successful.

As this is a very long delay there is no advantage in using
high-resolution timers thus switching this to msleep().

Signed-off-by: default avatarNicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent de901cc3

drivers/input/mouse/cyapa_gen3.c

+12 −15
Original line number Diff line number Diff line
@@ -789,7 +789,7 @@ static ssize_t cyapa_gen3_do_calibrate(struct device *dev, 
				     const char *buf, size_t count)

{

	struct cyapa *cyapa = dev_get_drvdata(dev);

	int tries;

	unsigned long timeout;

	int ret;



	ret = cyapa_read_byte(cyapa, CYAPA_CMD_DEV_STATUS);
@@ -812,31 +812,28 @@ static ssize_t cyapa_gen3_do_calibrate(struct device *dev, 
		goto out;

	}



	tries = 20;  /* max recalibration timeout 2s. */

	/* max recalibration timeout 2s. */

	timeout = jiffies + 2 * HZ;

	do {

		/*

		 * For this recalibration, the max time will not exceed 2s.

		 * The average time is approximately 500 - 700 ms, and we

		 * will check the status every 100 - 200ms.

		 */

		usleep_range(100000, 200000);



		msleep(100);

		ret = cyapa_read_byte(cyapa, CYAPA_CMD_DEV_STATUS);

		if (ret < 0) {

			dev_err(dev, "Error reading dev status: %d\n",

				ret);

			dev_err(dev, "Error reading dev status: %d\n", ret);

			goto out;

		}

		if ((ret & CYAPA_DEV_NORMAL) == CYAPA_DEV_NORMAL)

			break;

	} while (--tries);

		if ((ret & CYAPA_DEV_NORMAL) == CYAPA_DEV_NORMAL) {

			dev_dbg(dev, "Calibration successful.\n");

			goto out;

		}

	} while (time_is_after_jiffies(timeout));



	if (tries == 0) {

	dev_err(dev, "Failed to calibrate. Timeout.\n");

	ret = -ETIMEDOUT;

		goto out;

	}

	dev_dbg(dev, "Calibration successful.\n");



out:

	return ret < 0 ? ret : count;

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