From: Emmanuel Grumbach Date: Mon, 27 Oct 2014 07:14:32 +0000 (+0200) Subject: iwlwifi: pcie: introduce delay when waking up the device X-Git-Tag: firefly_0821_release~176^2~2717^2~28^2~17^2~89 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=01e58a281e6f0184e54af19a74de9a4012eeab25;p=firefly-linux-kernel-4.4.55.git iwlwifi: pcie: introduce delay when waking up the device In some rare cases, the firmware can put the device to sleep after the driver requested the access. This is because the access request can take a short time to be propagated to the firmware. If that happens, the driver may think that it has access since the firmware hasn't put the device to sleep yet, but right after the driver's check, the firmware might put the device to sleep. Warn when this happens by allowing the firmware to finish the "put the device sleep" flow so that the driver will not get access to the device. This will make the issue visible. This still doesn't fix the race, but at least it makes it more visible. Signed-off-by: Emmanuel Grumbach --- diff --git a/drivers/net/wireless/iwlwifi/pcie/trans.c b/drivers/net/wireless/iwlwifi/pcie/trans.c index 40a290603ead..d8727491fee5 100644 --- a/drivers/net/wireless/iwlwifi/pcie/trans.c +++ b/drivers/net/wireless/iwlwifi/pcie/trans.c @@ -1031,6 +1031,9 @@ static int iwl_trans_pcie_d3_resume(struct iwl_trans *trans, iwl_set_bit(trans, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ); iwl_set_bit(trans, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_FLAG_INIT_DONE); + if (trans->cfg->device_family == IWL_DEVICE_FAMILY_8000) + udelay(2); + ret = iwl_poll_bit(trans, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY, CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY, @@ -1233,6 +1236,8 @@ static bool iwl_trans_pcie_grab_nic_access(struct iwl_trans *trans, bool silent, /* this bit wakes up the NIC */ __iwl_trans_pcie_set_bit(trans, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ); + if (trans->cfg->device_family == IWL_DEVICE_FAMILY_8000) + udelay(2); /* * These bits say the device is running, and should keep running for diff --git a/drivers/net/wireless/iwlwifi/pcie/tx.c b/drivers/net/wireless/iwlwifi/pcie/tx.c index eb8e2984c5e9..4a4104eda9b8 100644 --- a/drivers/net/wireless/iwlwifi/pcie/tx.c +++ b/drivers/net/wireless/iwlwifi/pcie/tx.c @@ -1431,6 +1431,9 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans, trans_pcie->cmd_in_flight = true; __iwl_trans_pcie_set_bit(trans, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ); + if (trans->cfg->device_family == IWL_DEVICE_FAMILY_8000) + udelay(2); + ret = iwl_poll_bit(trans, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_VAL_MAC_ACCESS_EN, (CSR_GP_CNTRL_REG_FLAG_MAC_CLOCK_READY |