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cx231xx: Fix power ramping issue

Message ID CAGoCfix0L_POhtmVi8qstEcQ5xNCb+dpP0zoQjCaL9LUmFZ10A@mail.gmail.com (mailing list archive)
State Accepted
Headers show

Commit Message

Devin Heitmueller July 24, 2011, 6:44 p.m. UTC 
Attached is a patch which addresses the issue discussed by Mauro and
Gerd for the "-32" errors seen with the Hauppauge USBLive 2.

Devin
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Patch

cx231xx: Fix power ramp time to be consistent regardless of CONFIG_HZ

From: Devin Heitmueller <dheitmueller@kernellabs.com>

On platforms that have CONFIG_HZ set to 100, the power ramp time effectively
ends up being 10ms.  However, on those that have a higher CONFIG_HZ, the time
ends up *actually* being 5ms, which doesn't allow enough time for the hardware
to be fully powered up before attempting to address it via i2c.

Change the constant to 10ms, which is long enough for the hardware to power
up, and won't really be anymore time than it was previously on platforms
with CONFIG_HZ being 100.

Credit goes to Mauro Carvalho Chehab and Gerd Hoffmann who previously
investigated this issue.

Tested with the Hauppauge USBLive 2, with which the problem was readily
reproducible after setting CONFIG_HZ to 1000.

Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/drivers/media/video/cx231xx/cx231xx.h b/drivers/media/video/cx231xx/cx231xx.h
index b39b85e..472d169 100644
--- a/drivers/media/video/cx231xx/cx231xx.h
+++ b/drivers/media/video/cx231xx/cx231xx.h
@@ -43,7 +43,7 @@ 
 #include "cx231xx-conf-reg.h"
 
 #define DRIVER_NAME                     "cx231xx"
-#define PWR_SLEEP_INTERVAL              5
+#define PWR_SLEEP_INTERVAL              10
 
 /* I2C addresses for control block in Cx231xx */
 #define     AFE_DEVICE_ADDRESS		0x60