Commit 61c7f775 authored by Stefan Richter's avatar Stefan Richter Committed by Jody McIntyre
Browse files

ieee1394: write broadcast_channel only to select nodes (fixes device recognition)

Some old 1394-1995 SBP-2 bridges would hang if they received a broadcast write
request to BROADCAST_CHANNEL before the config ROM was read.  Affected devices
include Datafab MD2-FW2 2.5" HDD and SmartDisk VST FWCDRW-V8 portable CD writer.
The write request is now directed to specific nodes instead of being broadcast
to all nodes at once, and it is only performed if a previous read request at
this register succeeded.

Fixes an old interoperability problem which was perceived as a 2.6.14-specific

Signed-off-by: default avatarStefan Richter <>
Signed-off-by: default avatarJody McIntyre <>
parent c4fc108a
......@@ -1346,6 +1346,33 @@ static void nodemgr_update_pdrv(struct node_entry *ne)
/* Write the BROADCAST_CHANNEL as per IEEE1394a and This
* seems like an optional service but in the end it is practically mandatory
* as a consequence of these clauses.
* Note that we cannot do a broadcast write to all nodes at once because some
* pre-1394a devices would hang. */
static void nodemgr_irm_write_bc(struct node_entry *ne, int generation)
quadlet_t bc_remote, bc_local;
int ret;
if (!ne->host->is_irm || ne->generation != generation ||
ne->nodeid == ne->host->node_id)
bc_local = cpu_to_be32(ne->host->csr.broadcast_channel);
/* Check if the register is implemented and 1394a compliant. */
ret = hpsb_read(ne->host, ne->nodeid, generation, bc_addr, &bc_remote,
if (!ret && bc_remote & cpu_to_be32(0x80000000) &&
bc_remote != bc_local)
hpsb_node_write(ne, bc_addr, &bc_local, sizeof(bc_local));
static void nodemgr_probe_ne(struct host_info *hi, struct node_entry *ne, int generation)
struct device *dev;
......@@ -1357,6 +1384,8 @@ static void nodemgr_probe_ne(struct host_info *hi, struct node_entry *ne, int ge
if (!dev)
nodemgr_irm_write_bc(ne, generation);
/* If "needs_probe", then this is either a new or changed node we
* rescan totally. If the generation matches for an existing node
* (one that existed prior to the bus reset) we send update calls
......@@ -1429,9 +1458,7 @@ static int nodemgr_send_resume_packet(struct hpsb_host *host)
return ret;
/* Because we are a 1394a-2000 compliant IRM, we need to inform all the other
* nodes of the broadcast channel. (Really we're only setting the validity
* bit). Other IRM responsibilities go in here as well. */
/* Perform a few high-level IRM responsibilities. */
static int nodemgr_do_irm_duties(struct hpsb_host *host, int cycles)
quadlet_t bc;
......@@ -1440,13 +1467,8 @@ static int nodemgr_do_irm_duties(struct hpsb_host *host, int cycles)
if (!host->is_irm || host->irm_id == (nodeid_t)-1)
return 1;
host->csr.broadcast_channel |= 0x40000000; /* set validity bit */
bc = cpu_to_be32(host->csr.broadcast_channel);
hpsb_write(host, LOCAL_BUS | ALL_NODES, get_hpsb_generation(host),
&bc, sizeof(quadlet_t));
/* We are a 1394a-2000 compliant IRM. Set the validity bit. */
host->csr.broadcast_channel |= 0x40000000;
/* If there is no bus manager then we should set the root node's
* force_root bit to promote bus stability per the 1394
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