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| author | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2009-01-20 19:09:58 +0100 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2009-01-24 11:17:28 +0100 |
| commit | 64c634ef83991b390ec0503e61f16efb0ba3c60b (patch) | |
| tree | 8af40a878618572e51f4c0a3fc1dfbce028aa202 /block/deadline-iosched.c | |
| parent | 8b7b6afaa84708d08139daa08538ca3e56c351f1 (diff) | |
| download | op-kernel-dev-64c634ef83991b390ec0503e61f16efb0ba3c60b.zip op-kernel-dev-64c634ef83991b390ec0503e61f16efb0ba3c60b.tar.gz | |
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>
Diffstat (limited to 'block/deadline-iosched.c')
0 files changed, 0 insertions, 0 deletions
