Return-path: Received: from mx2.redhat.com ([66.187.237.31]:38365 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755432AbZHDMoW (ORCPT ); Tue, 4 Aug 2009 08:44:22 -0400 From: Stanislaw Gruszka To: linux-wireless@vger.kernel.org Cc: Zhu Yi , Reinette Chatre , "John W. Linville" , Stanislaw Gruszka , stable@kernel.org Subject: [PATCH 2.6.30] iwl3945: fix rfkill switch Date: Tue, 4 Aug 2009 14:35:50 +0200 Message-Id: <1249389350-4158-1-git-send-email-sgruszka@redhat.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 iwl3945 driver. We disable STATUS_RF_KILL_SW bit regardless of HW bit state. Also report to rfkill subsystem SW switch bit before HW switch bit to move rfkill subsystem to SOFT_BLOCK rather than HARD_BLOCK. Signed-off-by: Stanislaw Gruszka --- I'm not sure if this is good candidate for stable as this is not backport of upstream commit. Also I did not test this patch with other iwlwifi devices, only with iwl3945. drivers/net/wireless/iwlwifi/iwl-rfkill.c | 24 ++++++++++++++---------- 1 files changed, 14 insertions(+), 10 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/iwl-rfkill.c b/drivers/net/wireless/iwlwifi/iwl-rfkill.c index 2ad9faf..d6b6098 100644 --- a/drivers/net/wireless/iwlwifi/iwl-rfkill.c +++ b/drivers/net/wireless/iwlwifi/iwl-rfkill.c @@ -54,21 +54,28 @@ static int iwl_rfkill_soft_rf_kill(void *data, enum rfkill_state state) case RFKILL_STATE_UNBLOCKED: if (iwl_is_rfkill_hw(priv)) { err = -EBUSY; - goto out_unlock; + /* pass error to rfkill core to make it state HARD + * BLOCKED and disable software kill switch */ } iwl_radio_kill_sw_enable_radio(priv); break; case RFKILL_STATE_SOFT_BLOCKED: iwl_radio_kill_sw_disable_radio(priv); + /* rfkill->mutex lock 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 +139,11 @@ 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); -- 1.6.2.5