Re: Bus Reset Observations

[Olivier D. <dai...@el...>]

I noticed EXACTLY the same problem. Here is my debug info: (I added the output
of the Node Identification and status register (11'h0E8)

May 26 15:05:50 milk kernel: ohci1394_0: Bus reset
May 26 15:05:50 milk kernel: ohci1394_0: SelfID process finished but NodeID not
valid: 0800FFC0
May 26 15:05:50 milk kernel: ohci1394_0: irq_handler timeout event=0x00020000
May 26 15:05:50 milk kernel: ohci1394_0: Got phy packet ctx=0 ... discarded

The problem is that the device DOES recognize the cable insertion, but the
SelfID process terminates with an invalid NodeID. (it should be something like
0x8800FFC0 instead of 0x0800FFC0). The MSB (bit 31) of the quadlet says if the
1394 OHCI has a valid node number. The 27nd bit is the CPS (Cable Power Status
OK).

I noticed that when there is 2 OHCI cards (in Linux boxes) on the bus, there is
always one card that ends with an invalid NodeID and the other ends with a
valid NodeID.

My knowledge of the ohci driver (and ieee1394 in general) is not high enough to
track down the problem by now.

Olivier

Mark Knecht wrote:

> Hi,
>    I don't know whether to report this as a stack problem or a gscanbus
> problem. (I think stack...) I am seeing a very specific and repeatable
> problem. To me, at a high level, this looks like incorrect operation at the
> stack level. On my systems I believe that when the Linux based PC is not
> connected to any 1394 devices, and a cable to a 1394 device is inserted into
> the OHCI card, the 1394 stack does not recognize a cable insertion.
>
>    Can someone verify whether they are seeing or not seeing the same
> results?
>
> Thanks,
> Mark
>
>
> TESTS......
>
>    I have set up 3 PCs with RH 6.2, downloaded the 2.2.15 kernel, built it
> first with the patch, and then with the CVS tree. I have downloaded and
> installed 1394libraw from the CVS tree and installed that. I have downloaded
> gscanbus and am running it on all three PCs. Messages in /var/log look
> pretty reasonable based on how many devices are on the bus. I can set up a
> network with the 3 PCs and a few other peripherals, and sometimes get
> gscanbus to correctly see the topology identically on all three machines.
> (And sometimes not!)
>
>    For gscanbus I built a guid-resolv.conf file with the GUIDs of each PC
> and put the same file on all three PCs.
>
> ***** Test 1 *****
>
> Connect 2 PCs and a Sony CD drive. Start gscanbus.
>
> Observations:
> I see 2 PCs and one unknown device.
> If I pull the cable on the drive, I see 2 PCs. (Bus Reset detected)
> If I insert the cable, the unknown device comes back. (Bus Reset Detected)
> If I power off the drive, the unknown device disappears. (Bus Reset
> Detected)
> If I power the drive back up, the unknown device reappears. (Bus Reset
> Detected)
>
> *****************
>
> ***** Test 2 *****
>
> Connect 1 PC and the Sony CD drive. Start gscanbus.
>
> Observations:
>
> I see 1 PC and one unknown device.
> If I pull the cable, I see 1 PC. (Bus reset detected)
>
> If I insert the drive cable, the drive does not come back. (Bus Reset is not
> detected)
>
> If I power off the drive, no change in the screen, because the screen is
> incorrect right now. (Bus Reset Detected)
> If I power the drive back up, then unknown device reappears. (Bus Reset
> Detected)
>
>
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--
Olivier Daigle
Projet Harfang
(514) 396-8800 ext.7699