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authorStefan Richter <stefanr@s5r6.in-berlin.de>2009-01-20 19:10:58 +0100
committerStefan Richter <stefanr@s5r6.in-berlin.de>2009-01-24 11:17:27 +0100
commit8b7b6afaa84708d08139daa08538ca3e56c351f1 (patch)
tree91b1d27a08f6e28c13f8163cc2dfbba4022029f0 /drivers/firewire
parentb006854955254a971096c120d4ef115a7c6145fb (diff)
firewire: ohci: 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 . In a quick test with a JVC camcorder (which didn't malfunction like the reported camcorders), this change decreased the number of ack_busy_X from 16 in three runs of dvgrab to 4 in three runs of the same capture duration. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Diffstat (limited to 'drivers/firewire')
-rw-r--r--drivers/firewire/fw-ohci.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index 9bedd6159f2..6d19828a93a 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -226,7 +226,7 @@ static inline struct fw_ohci *fw_ohci(struct fw_card *card)
#define CONTEXT_DEAD 0x0800
#define CONTEXT_ACTIVE 0x0400
-#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