Date: Tue, 20 Jan 2009 19:09:58 +0100 (CET) From: Stefan Richter Subject: 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 --- drivers/ieee1394/ohci1394.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux/drivers/ieee1394/ohci1394.h =================================================================== --- linux.orig/drivers/ieee1394/ohci1394.h +++ linux/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