Re: FireWire + Apple PB G3: some success

On Thu, Feb 24, 2000 at 05:44:53AM +0300, Maxim S. Shatskih wrote:

quoted

It's not seen because the driver is stuck in bus reset.  The most
probable reason is that DMA is not working.  I can't think of a reason
right now (since it does work on another PPC).

I've had this problem on NT4. Are you sure that the DMA enable bit in PCI
config space is set?

To quote Albert's patch:

 +       pci_read_config_word (dev, PCI_COMMAND, &w);
 +       pci_write_config_word (dev, PCI_COMMAND, w | PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY | PCI_COMMAND_IO);

He sets the PCI master flag (which should be the only thing disabling /
enabling DMA in general).  In the standard sources pci_set_master() is
used, which does the same.

Setting PCI_COMMAND_IO on the other hand is unneccessary since the
PCILynx only uses memory mapped I/O (if I understand PCI config
correctly).  I don't know if this flag is harmful if there are no I/O
ports.

--
          Andreas E. Bombe [off-list ref]
http://home.pages.de/~andreas.bombe/                DSA key 0x04880A44

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