ieee1394: ohci1394: increase AT req. retries, fix ack_busy_X from Panasonic camcorders and others
Camcorders have a tendency to fail read requests to their config ROM and
write request to their FCP command register with ack_busy_X. This has
become a problem with newer kernels and especially Panasonic camcorders,
causing AV/C in dvgrab and kino to fail. Dvgrab for example frequently
logs "send oops"; kino reports loss of AV/C control. I suspect that
lower CPU scheduling latencies in newer kernels made this issue more
prominent now.
According to
https://sourceforge.net/tracker/?func=detail&atid=114103&aid=2492640&group_id=14103
this can be fixed by configuring the FireWire controller for more
hardware retries for request transmission; these retries are evidently
more successful than libavc1394's own retry loop (typically 3 tries on
top of hardware retries).
Presumably the same issue has been reported at
https://bugzilla.redhat.com/show_bug.cgi?id=449252 and
https://bugzilla.redhat.com/show_bug.cgi?id=477279 .
Tested-by: Mathias Beilstein
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/ieee1394/ohci1394.h b/drivers/ieee1394/ohci1394.h
index 4320bf01..7fb8ab9 100644
--- a/drivers/ieee1394/ohci1394.h
+++ b/drivers/ieee1394/ohci1394.h
@@ -26,7 +26,7 @@
#define OHCI1394_DRIVER_NAME "ohci1394"
-#define OHCI1394_MAX_AT_REQ_RETRIES 0x2
+#define OHCI1394_MAX_AT_REQ_RETRIES 0xf
#define OHCI1394_MAX_AT_RESP_RETRIES 0x2
#define OHCI1394_MAX_PHYS_RESP_RETRIES 0x8
#define OHCI1394_MAX_SELF_ID_ERRORS 16
