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firewire: ohci: fix IR/IT context mask mixup

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This bug was present in firewire-ohci since day one:  The number of
available isochronous receive DMA contexts was mixed up with that of
available isochronous transmit DMA contexts.

This is harmless on a few chips which offer the same number of contexts
in both directions, but most chips nowadays implement only the standard
minimum of 4 IR contexts, but 8 IT contexts.  If a user attempted to run
a lot of IR contexts at once, results with more than four were therefore
unpredictable.  I suppose the controller would simply refuse to start
DMA of any unimplemented context.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Stefan Richter 2010-02-21 17:58:52 +01:00
parent 3e9cc2f3b7
commit 4802f16d51
1 changed files with 8 additions and 8 deletions
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16
drivers/firewire/ohci.c
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@ -2395,18 +2395,18 @@ static int __devinit pci_probe(struct pci_dev *dev,
OHCI1394_AsRspTrContextControlSet, handle_at_packet);
reg_write(ohci, OHCI1394_IsoRecvIntMaskSet, ~0);
ohci->it_context_mask = reg_read(ohci, OHCI1394_IsoRecvIntMaskSet);
reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, ~0);
size = sizeof(struct iso_context) * hweight32(ohci->it_context_mask);
ohci->it_context_list = kzalloc(size, GFP_KERNEL);
reg_write(ohci, OHCI1394_IsoXmitIntMaskSet, ~0);
ohci->ir_context_channels = ~0ULL;
ohci->ir_context_mask = reg_read(ohci, OHCI1394_IsoXmitIntMaskSet);
reg_write(ohci, OHCI1394_IsoXmitIntMaskClear, ~0);
ohci->ir_context_mask = reg_read(ohci, OHCI1394_IsoRecvIntMaskSet);
reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, ~0);
size = sizeof(struct iso_context) * hweight32(ohci->ir_context_mask);
ohci->ir_context_list = kzalloc(size, GFP_KERNEL);
reg_write(ohci, OHCI1394_IsoXmitIntMaskSet, ~0);
ohci->it_context_mask = reg_read(ohci, OHCI1394_IsoXmitIntMaskSet);
reg_write(ohci, OHCI1394_IsoXmitIntMaskClear, ~0);
size = sizeof(struct iso_context) * hweight32(ohci->it_context_mask);
ohci->it_context_list = kzalloc(size, GFP_KERNEL);
if (ohci->it_context_list == NULL || ohci->ir_context_list == NULL) {
err = -ENOMEM;
goto fail_contexts;