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From: Stefan Richter on 18 Mar 2010 19:40
The modalias string of devices that represent units on a FireWire node
did not show Module_ID entries within unit directories. This was
because firewire-core searched only the root directory of the
configuration ROM for a Model_ID entry.

We now search first the root directory, then the unit directory. IOW
honor a unit directory's Model_ID if present, otherwise fall back to the
root directory's model ID (if present).

Furthermore, apply the same change to Vendor_ID. This had the same
issue but it was less apparent because most devices provide Vendor_ID
only in the root directory.

And finally, also use this strategy for the remaining two IDs in the
modalias, Specifier_ID and Version. It does not actually make sense to
look for them elsewhere than in the unit directory because they are
mandatory there. However, a uniform search order simplifies the
implementation and has no adverse affect in practice.

Side notes:
- The older counterpart of this, nodemgr.c of ieee1394, looked for
Vendor_ID first in the root directory, then in the unit directory,
and for Model_ID only in the unit directory.
- There is a single mainline driver which requires Vendor_ID and
Model_ID --- the firedtv driver. This one worked because FireDTVs
provide Vendor_ID in the root directory and Model_ID identically in
root directory and unit directory.
- Apart from firedtv, there are currently no drivers known to me
(including userspace drivers) that look at the Vendor_ID or Model_ID
of the modalias.

Reported-by: Maciej �enczykowski <zenczykowski(a)gmail.com>
Signed-off-by: Stefan Richter <stefanr(a)s5r6.in-berlin.de>
---
drivers/firewire/core-device.c | 40 ++++++++++++---------------------
1 file changed, 14 insertions(+), 26 deletions(-)

Index: b/drivers/firewire/core-device.c
===================================================================
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -180,44 +180,32 @@ static int fw_unit_match(struct device *
return 0;
}

-static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
+static void get_modalias_ids(const u32 *directory, int *id)
{
- struct fw_device *device = fw_parent_device(unit);
struct fw_csr_iterator ci;
-
int key, value;
- int vendor = 0;
- int model = 0;
- int specifier_id = 0;
- int version = 0;

- fw_csr_iterator_init(&ci, &device->config_rom[5]);
+ fw_csr_iterator_init(&ci, directory);
while (fw_csr_iterator_next(&ci, &key, &value)) {
switch (key) {
- case CSR_VENDOR:
- vendor = value;
- break;
- case CSR_MODEL:
- model = value;
- break;
+ case CSR_VENDOR: id[0] = value; break;
+ case CSR_MODEL: id[1] = value; break;
+ case CSR_SPECIFIER_ID: id[2] = value; break;
+ case CSR_VERSION: id[3] = value; break;
}
}
+}

- fw_csr_iterator_init(&ci, unit->directory);
- while (fw_csr_iterator_next(&ci, &key, &value)) {
- switch (key) {
- case CSR_SPECIFIER_ID:
- specifier_id = value;
- break;
- case CSR_VERSION:
- version = value;
- break;
- }
- }
+static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
+{
+ int id[] = {0, 0, 0, 0};
+
+ get_modalias_ids(&fw_parent_device(unit)->config_rom[5], id);
+ get_modalias_ids(unit->directory, id);

return snprintf(buffer, buffer_size,
"ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
- vendor, model, specifier_id, version);
+ id[0], id[1], id[2], id[3]);
}

static int fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)

--
Stefan Richter
-=====-==-=- --== =--==
http://arcgraph.de/sr/

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Prev: 2.6.33 GP fault only when built with tracing
Next: [PATCH 2/2] firewire: core: align driver match with modalias