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Commit 5022a208 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
Browse files

[media] em28xx: properly implement AC97 wait code 



Instead of assuming that msleep() is precise, use a jiffies
based code to wait for AC97 to be available.

Reviewed-by: default avatarFrank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: default avatarMauro Carvalho Chehab <m.chehab@samsung.com>
parent 2276bf70

drivers/media/usb/em28xx/em28xx-core.c

+5 −2
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
 */



#include <linux/init.h>

#include <linux/jiffies.h>

#include <linux/list.h>

#include <linux/module.h>

#include <linux/slab.h>
@@ -252,16 +253,18 @@ EXPORT_SYMBOL_GPL(em28xx_toggle_reg_bits); 
 */

static int em28xx_is_ac97_ready(struct em28xx *dev)

{

	int ret, i;

	unsigned long timeout = jiffies + msecs_to_jiffies(EM28XX_AC97_XFER_TIMEOUT);

	int ret;



	/* Wait up to 50 ms for AC97 command to complete */

	for (i = 0; i < 10; i++, msleep(5)) {

	while (time_is_after_jiffies(timeout)) {

		ret = em28xx_read_reg(dev, EM28XX_R43_AC97BUSY);

		if (ret < 0)

			return ret;



		if (!(ret & 0x01))

			return 0;

		msleep(5);

	}



	em28xx_warn("AC97 command still being executed: not handled properly!\n");

drivers/media/usb/em28xx/em28xx.h

+3 −0
Original line number Diff line number Diff line
@@ -186,6 +186,9 @@ 
/* time in msecs to wait for i2c writes to finish */

#define EM2800_I2C_XFER_TIMEOUT		20



/* time in msecs to wait for AC97 xfers to finish */

#define EM28XX_AC97_XFER_TIMEOUT	100



/* max. number of button state polling addresses */

#define EM28XX_NUM_BUTTON_ADDRESSES_MAX		5