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authorStefan Richter <stefanr@s5r6.in-berlin.de>2008-04-12 16:31:25 -0400
committerStefan Richter <stefanr@s5r6.in-berlin.de>2008-04-18 11:55:35 -0400
commitd34316a4bdcd4fef050da584401c7f4ed22482f2 (patch)
tree4b6650cc815be1364ba4d9952b18818c5b602047 /drivers/firewire/fw-device.c
parent08ddb2f4c270b5dff063f7dbcd7e9248a52e7c65 (diff)
firewire: fw-ohci: work around generation bug in TI controllers (fix AV/C and more)
Unlike the ohci1394 driver, fw-ohci uses the selfIDGeneration field of bus reset packets to determine the generation of incoming requests as per OHCI 1.1 clause 8.4.2.3. This is more precise --- provided that the controller inserts the correct generation. Texas Instruments chips often don't. This prevented the transmission of response packets, which for example broke AV/C transactions as used when communicating with miniDV cameras and any other AV/C devices. There is apparently no way to detect and adjust incorrect generations. Therefore we ignore the generation of bus reset packets from TI chips and use the generation of the self ID buffer instead. Alas this is received at a slightly wrong time. In rare cases, this could cause us to not respond to legitimate requests or to respond to expired requests. (The latter is less likely because the bus reset packet AR event is typically handled before the self ID complete event.) Bug reported by Mladen Kuntner, who was extraordinarily patient while dealing with the driver maintainers. Fix confirmed to be required and effective for TSB82AA2 and a TSB43AB22 or TSB43AB22A. https://bugzilla.redhat.com/show_bug.cgi?id=243081 Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Diffstat (limited to 'drivers/firewire/fw-device.c')
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