V4L/DVB (3639): Reduce FWSEND due to certain I2C bus adapter limits

The FWSEND parameter controls the size of the firmware chunks sent
down the I2C bus to the chip.  Previously this had been set to 1024
but unfortunately some I2C implementations can't transfer data in such
big gulps.  Specifically, the pvrusb2 driver has a hard limit of
around 60 bytes, due to the encapsulation there of I2C traffic into
USB messages.  So we have to significantly reduce this parameter.
Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

diff --git a/drivers/media/video/cx25840/cx25840-firmware.c b/drivers/media/video/cx25840/cx25840-firmware.c
index 18dd347..f59ced1 100644 (file)
--- a/drivers/media/video/cx25840/cx25840-firmware.c
+++ b/drivers/media/video/cx25840/cx25840-firmware.c
@@ -25,7 +25,17 @@
 #include "cx25840-core.h"
 
 #define FWFILE "v4l-cx25840.fw"
-#define FWSEND 1024
+
+/*
+ * Mike Isely <isely@pobox.com> - The FWSEND parameter controls the
+ * size of the firmware chunks sent down the I2C bus to the chip.
+ * Previously this had been set to 1024 but unfortunately some I2C
+ * implementations can't transfer data in such big gulps.
+ * Specifically, the pvrusb2 driver has a hard limit of around 60
+ * bytes, due to the encapsulation there of I2C traffic into USB
+ * messages.  So we have to significantly reduce this parameter.
+ */
+#define FWSEND 48
 
 #define FWDEV(x) &((x)->adapter->dev)