Messages in this thread Patch in this message | | | Date | Fri, 04 Sep 2009 17:14:10 -0700 | From | Greg KH <> | Subject | [patch 35/71] iwl3945: fix rfkill switch |
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2.6.30-stable review patch. If anyone has any objections, please let us know.
------------------ From: Stanislaw Gruszka <sgruszka@redhat.com>
(Not needed upstream, due to the major rewrite in 2.6.31)
Due to rfkill and iwlwifi mishmash of SW / HW killswitch representation, we have race conditions which make unable turn wifi radio on, after enable and disable again killswitch. I can observe this problem on my laptop with iwl3945 device.
In rfkill core HW switch and SW switch are separate 'states'. Device can be only in one of 3 states: RFKILL_STATE_SOFT_BLOCKED, RFKILL_STATE_UNBLOCKED, RFKILL_STATE_HARD_BLOCKED. Whereas in iwlwifi driver we have separate bits STATUS_RF_KILL_HW and STATUS_RF_KILL_SW for HW and SW switches - radio can be turned on, only if both bits are cleared.
In this particular race conditions, radio can not be turned on if in driver STATUS_RF_KILL_SW bit is set, and rfkill core is in state RFKILL_STATE_HARD_BLOCKED, because rfkill core is unable to call rfkill->toggle_radio(). This situation can be entered in case:
- killswitch is turned on - rfkill core 'see' button change first and move to RFKILL_STATE_SOFT_BLOCKED also call ->toggle_radio() and STATE_RF_KILL_SW in driver is set - iwl3945 get info about button from hardware to set STATUS_RF_KILL_HW bit and force rfkill to move to RFKILL_STATE_HARD_BLOCKED - killsiwtch is turend off - driver clear STATUS_RF_KILL_HW - rfkill core is unable to clear STATUS_RF_KILL_SW in driver
Additionally call to rfkill_epo() when STATUS_RF_KILL_HW in driver is set cause move to the same situation.
In 2.6.31 this problem is fixed due to _total_ rewrite of rfkill subsystem. This is a quite small fix for 2.6.30.x in iwlwifi driver. We are changing internal rfkill state to always have below relations true:
STATUS_RF_KILL_HW=1 STATUS_RF_KILL_SW=1 <-> RFKILL_STATUS_SOFT_BLOCKED STATUS_RF_KILL_HW=0 STATUS_RF_KILL_SW=1 <-> RFKILL_STATUS_SOFT_BLOCKED STATUS_RF_KILL_HW=1 STATUS_RF_KILL_SW=0 <-> RFKILL_STATUS_HARD_BLOCKED STATUS_RF_KILL_HW=0 STATUS_RF_KILL_SW=0 <-> RFKILL_STATUS_UNBLOCKED
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Acked-by: Reinette Chatre <reinette.chatre@intel.com> Acked-by: John W. Linville <linville@tuxdriver.com>
--- drivers/net/wireless/iwlwifi/iwl-rfkill.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-)
--- a/drivers/net/wireless/iwlwifi/iwl-rfkill.c +++ b/drivers/net/wireless/iwlwifi/iwl-rfkill.c @@ -53,22 +53,31 @@ static int iwl_rfkill_soft_rf_kill(void switch (state) { case RFKILL_STATE_UNBLOCKED: if (iwl_is_rfkill_hw(priv)) { + /* pass error to rfkill core, make it state HARD + * BLOCKED (rfkill->mutex taken) and disable + * software kill switch */ err = -EBUSY; - goto out_unlock; + priv->rfkill->state = RFKILL_STATE_HARD_BLOCKED; } iwl_radio_kill_sw_enable_radio(priv); break; case RFKILL_STATE_SOFT_BLOCKED: iwl_radio_kill_sw_disable_radio(priv); + /* rfkill->mutex is taken */ + if (priv->rfkill->state == RFKILL_STATE_HARD_BLOCKED) { + /* force rfkill core state to be SOFT BLOCKED, + * otherwise core will be unable to disable software + * kill switch */ + priv->rfkill->state = RFKILL_STATE_SOFT_BLOCKED; + } break; default: IWL_WARN(priv, "we received unexpected RFKILL state %d\n", state); break; } -out_unlock: - mutex_unlock(&priv->mutex); + mutex_unlock(&priv->mutex); return err; } @@ -132,14 +141,11 @@ void iwl_rfkill_set_hw_state(struct iwl_ if (!priv->rfkill) return; - if (iwl_is_rfkill_hw(priv)) { + if (iwl_is_rfkill_sw(priv)) + rfkill_force_state(priv->rfkill, RFKILL_STATE_SOFT_BLOCKED); + else if (iwl_is_rfkill_hw(priv)) rfkill_force_state(priv->rfkill, RFKILL_STATE_HARD_BLOCKED); - return; - } - - if (!iwl_is_rfkill_sw(priv)) - rfkill_force_state(priv->rfkill, RFKILL_STATE_UNBLOCKED); else - rfkill_force_state(priv->rfkill, RFKILL_STATE_SOFT_BLOCKED); + rfkill_force_state(priv->rfkill, RFKILL_STATE_UNBLOCKED); } EXPORT_SYMBOL(iwl_rfkill_set_hw_state);
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