Re: Bus Reset
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From: Sebastien R. <Seb...@sy...> - 2000-04-17 04:57:57
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>>>>> "Jeff" == Jeff Mak <Jef...@ef...> writes: Jeff> I am making use of raw1394 (dev_open) to connect to the other node Jeff> through OHCI kernel driver, when there is a change in power status at Jeff> PHY of the other node, a bus reset would be generated from the hardware. Jeff> Is it true that the connection in between would be lost? In other Jeff> words, can I send any other command to the target node using the same Jeff> handle? I know that this is not OHCI specific question but since I am Jeff> using OHCI kernel driver written by you, I believe you may have some Jeff> experience on that. I don't think bus reset are handled properly yet in the current version of the linux ieee1394 driver. If a bus reset occurs, the node numbers on the bus are re-assigned, and I don't think that libraw is designed to deal with that situation (I might be wrong though). Especially, the ohci driver receives a specific phy packet that indicates precisely when the bus configuration has been modified, but this packet is currently being discarded since the subsystem doesn't accept it... I have to talk to Andreas about that. Jeff> The reason why I ask this question is: I am currently trying to talk to Jeff> a target node which has a "wake up" feature. In other words, if the Jeff> target node is idle for period of time, it will try to shutdown itself Jeff> until it receives a "wake up" command from my linux box. However, when Jeff> the target node is idle and auto shutoff. Bus reset would be generated Jeff> causing I cannot get the respond from the target node anymore using the Jeff> same raw1394_handle. I have tried to deactivate the bus reset event on Jeff> interrupt of OHCI driver but it is not working. I believe deactivating Jeff> the interrupt event mask on bus reset is just ignore the bus reset on Jeff> kernel driver side. Do you mean that everytime the node goes in 'sleep' mode, a bus reset is generated ??? Jeff> I suppose if the target node get the power from the firewire bus and my Jeff> firewire card is a power supplier, there shouldn't be any bus reset even Jeff> if the target node is in power off mode. Is my understanding correct? Jeff> I know that this is IEEE1394 specific and if you have any suggestion, Jeff> please let me know. Sorry I don't know about that particular point of the ieee1394 standard. -- Sebastien Rougeaux RSISE, The Australian National University |