rfkill_force_state() is used to update the rfkill core's idea of what is
really happening RIGHT NOW to the transmitter hardware in a PUSH model.
rfkill->get_state() does the same, in a PULL model.
Neither of them change the real hardware radio state through a call to
rfkill->toggle_radio() or anything of the sort, so they must deal with the
real, current state of the hardware.
Change some documentation to make that more clear (I hope).
Signed-off-by: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx>
Cc: Ivo van Doorn <IvDoorn@xxxxxxxxx>
Cc: Larry Finger <Larry.Finger@xxxxxxxxxxxx>
---
Documentation/rfkill.txt | 10 ++++++++++
include/linux/rfkill.h | 3 +++
net/rfkill/rfkill.c | 3 +++
3 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/Documentation/rfkill.txt b/Documentation/rfkill.txt
index b65f079..0143f1e 100644
--- a/Documentation/rfkill.txt
+++ b/Documentation/rfkill.txt
@@ -461,6 +461,16 @@ mandatory when the device has a hardware rfkill line, or when something else
like the firmware could cause its state to be changed without going through the
rfkill class.
+**** ATTENTION ****
+Both the state returned by the rfkill->get_state() hook, and the state
+passed to rfkill_force_state() MUST BE THE REAL, CURRENT STATE OF THE
+HARDWARE TRANSMITTER. Never use for these functions the "desired" state,
+"user requested" state, or anything of the sort.
+
+Also, be warned that rfkill_force_state() cannot be called from atomic context,
+so interrupt handlers will have to make use of a workqueue to do it.
+**** ATTENTION ****
+
Some hardware provides events when its status changes. In these cases, it is
best for the driver to not provide a get_state hook, and instead register the
rfkill class *already* with the correct status, and keep it updated using
diff --git a/include/linux/rfkill.h b/include/linux/rfkill.h
index 4cd64b0..92b9c72 100644
--- a/include/linux/rfkill.h
+++ b/include/linux/rfkill.h
@@ -80,6 +80,9 @@ enum rfkill_state {
* may be called from atomic context, should return 0 on success.
* Either this handler OR judicious use of rfkill_force_state() is
* MANDATORY for any driver capable of RFKILL_STATE_HARD_BLOCKED.
+ * THIS HOOK MUST RETURN THE CURRENT, REAL STATE OF THE HARDWARE
+ * TRANSMITTER, and not the "desired state", "user requested state"
+ * or anything of the sort.
* @led_trigger: A LED trigger for this button's LED.
* @dev: Device structure integrating the switch into device tree.
* @node: Used to place switch into list of all switches known to the
diff --git a/net/rfkill/rfkill.c b/net/rfkill/rfkill.c
index f949a48..64a53f1 100644
--- a/net/rfkill/rfkill.c
+++ b/net/rfkill/rfkill.c
@@ -333,6 +333,9 @@ EXPORT_SYMBOL_GPL(rfkill_restore_states);
* a notification by the firmware/hardware of the current *real*
* state of the radio rfkill switch.
*
+ * The state passed to this function MUST MATCH THE CURRENT,
+ * REAL HARDWARE STATE OF THE TRANSMITTER.
+ *
* Devices which are subject to external changes on their rfkill
* state (such as those caused by a hardware rfkill line) MUST
* have their driver arrange to call rfkill_force_state() as soon
--
1.5.6.5
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