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[v3,16/24] em28xx: properly implement AC97 wait code

Message ID 1388232976-20061-17-git-send-email-mchehab@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mauro Carvalho Chehab Dec. 28, 2013, 12:16 p.m. UTC
From: Mauro Carvalho Chehab <m.chehab@samsung.com>

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

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
---
 drivers/media/usb/em28xx/em28xx-core.c | 7 +++++--
 drivers/media/usb/em28xx/em28xx.h      | 5 ++++-
 2 files changed, 9 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index 818248d3fd28..36b2f1ab4474 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>
@@ -254,16 +255,18 @@  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(EM2800_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 9d6f43e4681f..ac79501f5d9f 100644
--- a/drivers/media/usb/em28xx/em28xx.h
+++ b/drivers/media/usb/em28xx/em28xx.h
@@ -182,9 +182,12 @@ 
 
 #define EM28XX_INTERLACED_DEFAULT 1
 
-/* time in msecs to wait for i2c writes to finish */
+/* time in msecs to wait for i2c xfers to finish */
 #define EM2800_I2C_XFER_TIMEOUT		20
 
+/* time in msecs to wait for AC97 xfers to finish */
+#define EM2800_AC97_XFER_TIMEOUT	100
+
 /* max. number of button state polling addresses */
 #define EM28XX_NUM_BUTTON_ADDRESSES_MAX		5