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| author | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2009-01-20 21:10:58 +0300 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2009-01-24 13:17:27 +0300 |
| commit | 8b7b6afaa84708d08139daa08538ca3e56c351f1 (patch) | |
| tree | 91b1d27a08f6e28c13f8163cc2dfbba4022029f0 | |
| parent | b006854955254a971096c120d4ef115a7c6145fb (diff) | |
| download | linux-8b7b6afaa84708d08139daa08538ca3e56c351f1.tar.xz | |
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>
| -rw-r--r-- | drivers/firewire/fw-ohci.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c index 9bedd6159f28..6d19828a93a5 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 |