On Tue, Aug 04, 2009 at 08:49:51AM -0400, John W. Linville wrote: > On Tue, Aug 04, 2009 at 02:35:50PM +0200, 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 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 <sgruszka@xxxxxxxxxx> > > --- > > 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. > > stable is about the only place it can go, since it fixes a problem > that doesn't exist in 2.6.31... Do you ack this for inclusion in 2.6.30-stable? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
