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-rw-r--r--drivers/firewire/fw-ohci.c15
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index ce18bab3f9d..4789300b824 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -950,8 +950,19 @@ at_context_queue_packet(struct context *ctx, struct fw_packet *packet)
DESCRIPTOR_IRQ_ALWAYS |
DESCRIPTOR_BRANCH_ALWAYS);
- /* FIXME: Document how the locking works. */
- if (ohci->generation != packet->generation) {
+ /*
+ * If the controller and packet generations don't match, we need to
+ * bail out and try again. If IntEvent.busReset is set, the AT context
+ * is halted, so appending to the context and trying to run it is
+ * futile. Most controllers do the right thing and just flush the AT
+ * queue (per section 7.2.3.2 of the OHCI 1.1 specification), but
+ * some controllers (like a JMicron JMB381 PCI-e) misbehave and wind
+ * up stalling out. So we just bail out in software and try again
+ * later, and everyone is happy.
+ * FIXME: Document how the locking works.
+ */
+ if (ohci->generation != packet->generation ||
+ reg_read(ohci, OHCI1394_IntEventSet) & OHCI1394_busReset) {
if (packet->payload_length > 0)
dma_unmap_single(ohci->card.device, payload_bus,
packet->payload_length, DMA_TO_DEVICE);