Message ID | 1250166548-2548-1-git-send-email-sgruszka@redhat.com (mailing list archive) |
---|---|
State | Not Applicable, archived |
Headers | show |
On Thu, 2009-08-13 at 05:29 -0700, Stanislaw Gruszka wrote: > 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> > --- > Patch was tested by me only with iwl3945 device. Fortunately I have not encountered these race conditions on my system. Even so, I tested this on a 5100 system and it behaves as expected wrt rfkill. Acked-by: Reinette Chatre <reinette.chatre@intel.com> Reinette -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Aug 13, 2009 at 10:12:06AM -0700, reinette chatre wrote: > On Thu, 2009-08-13 at 05:29 -0700, Stanislaw Gruszka wrote: > > 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> > > --- > > Patch was tested by me only with iwl3945 device. > > Fortunately I have not encountered these race conditions on my system. > Even so, I tested this on a 5100 system and it behaves as expected wrt > rfkill. > > Acked-by: Reinette Chatre <reinette.chatre@intel.com> ACK for stable
diff --git a/drivers/net/wireless/iwlwifi/iwl-rfkill.c b/drivers/net/wireless/iwlwifi/iwl-rfkill.c index 2ad9faf..fc3a95f 100644 --- 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 *data, enum rfkill_state state) 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_priv *priv) 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);
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> --- Patch was tested by me only with iwl3945 device. drivers/net/wireless/iwlwifi/iwl-rfkill.c | 26 ++++++++++++++++---------- 1 files changed, 16 insertions(+), 10 deletions(-)