firewire: fw-ohci: don't append to AT context when it's not active

[linux-2.6-omap-h63xx.git] / drivers / firewire / fw-ohci.c

diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index ce18bab3f9d5be3f0824b962953b356cda7dfc72..4789300b8241ae7481bd9471d053644fd7a94623 100644 (file)
--- 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);