From 5022a2088687baeda87b03889d0791b1b908266b Mon Sep 17 00:00:00 2001
From: Mauro Carvalho Chehab <m.chehab@samsung.com>
Date: Fri, 27 Dec 2013 00:28:57 -0300
Subject: [PATCH] [media] em28xx: properly implement AC97 wait code
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Instead of assuming that msleep() is precise, use a jiffies
based code to wait for AC97 to be available.
Reviewed-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---
drivers/media/usb/em28xx/em28xx-core.c | 7 +++++--
drivers/media/usb/em28xx/em28xx.h | 3 +++
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index b5f49703f7ce..b6dc3327c51c 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -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");
diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h
index b792f2225abd..b0aa8497c1a9 100644
--- a/drivers/media/usb/em28xx/em28xx.h
+++ b/drivers/media/usb/em28xx/em28xx.h
@@ -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
--
2.30.9