git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From stefanr@s5r6.in-berlin.de  Sun Feb  8 12:42:41 2009
   2 From: Stefan Richter <stefanr@s5r6.in-berlin.de>
   3 Date: Sat, 7 Feb 2009 13:08:41 +0100 (CET)
   4 Subject: firewire: ohci: increase AT req. retries, fix ack_busy_X from Panasonic camcorders and others
   5 To: stable@kernel.org
   6 Message-ID: <tkrat.c40219855501ef69@s5r6.in-berlin.de>
   7 Content-Disposition: INLINE
   8
   9 From: Stefan Richter <stefanr@s5r6.in-berlin.de>
  10
  11 Commit 8b7b6afaa84708d08139daa08538ca3e56c351f1 upstream.
  12
  13 Camcorders have a tendency to fail read requests to their config ROM and
  14 write request to their FCP command register with ack_busy_X.  This has
  15 become a problem with newer kernels and especially Panasonic camcorders,
  16 causing AV/C in dvgrab and kino to fail.  Dvgrab for example frequently
  17 logs "send oops"; kino reports loss of AV/C control.  I suspect that
  18 lower CPU scheduling latencies in newer kernels made this issue more
  19 prominent now.
  20
  21 According to
  22 https://sourceforge.net/tracker/?func=detail&atid=114103&aid=2492640&group_id=14103
  23 this can be fixed by configuring the FireWire controller for more
  24 hardware retries for request transmission; these retries are evidently
  25 more successful than libavc1394's own retry loop (typically 3 tries on
  26 top of hardware retries).
  27
  28 Presumably the same issue has been reported at
  29 https://bugzilla.redhat.com/show_bug.cgi?id=449252 and
  30 https://bugzilla.redhat.com/show_bug.cgi?id=477279 .
  31
  32 In a quick test with a JVC camcorder (which didn't malfunction like the
  33 reported camcorders), this change decreased the number of ack_busy_X
  34 from 16 in three runs of dvgrab to 4 in three runs of the same capture
  35 duration.
  36
  37 Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
  38 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  39
  40 ---
  41  drivers/firewire/fw-ohci.c |    2 +-
  42  1 file changed, 1 insertion(+), 1 deletion(-)
  43
  44 --- a/drivers/firewire/fw-ohci.c
  45 +++ b/drivers/firewire/fw-ohci.c
  46 @@ -226,7 +226,7 @@ static inline struct fw_ohci *fw_ohci(st
  47  #define CONTEXT_DEAD   0x0800
  48  #define CONTEXT_ACTIVE 0x0400
  49
  50 -#define OHCI1394_MAX_AT_REQ_RETRIES    0x2
  51 +#define OHCI1394_MAX_AT_REQ_RETRIES    0xf
  52  #define OHCI1394_MAX_AT_RESP_RETRIES   0x2
  53  #define OHCI1394_MAX_PHYS_RESP_RETRIES 0x8
  54