Subject: Re: [PATCH RFC] iwlwifi: add basic runtime PM support

From: "Yan, Zheng" <[email-masked]>
Date: Mon, 09 Jan 2012 09:37:07 +0800

On 01/06/2012 11:14 PM, wwguy wrote:
> Hi Zheng,
> 
> On Fri, 2012-01-06 at 10:41 +0800, Yan, Zheng wrote:
>> This simple patch adds open/close based runtime PM support to the iwlwifi driver.
>> Namely, make the driver suspend the device after shutting down the interface and
>> resume the device when activating the interface. In my test, suspending the device
>> can save about 0.4 watt power. The shortcoming is that the device no longer generate
>> rfkill changes interrupt.
>>
>> Signed-off-by: Zheng Yan <[email-masked]>
>> ---
>> diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
>> index e0e9a3d..c0b7b85 100644
>> --- a/drivers/net/wireless/iwlwifi/iwl-agn.c
>> +++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
>> @@ -38,6 +38,7 @@
>>  #include <linux/firmware.h>
>>  #include <linux/etherdevice.h>
>>  #include <linux/if_arp.h>
>> +#include <linux/pm_runtime.h>
>>  
>>  #include <net/mac80211.h>
>>  
>> @@ -1755,6 +1756,8 @@ static int iwlagn_mac_start(struct ieee80211_hw *hw)
>>  	struct iwl_priv *priv = hw->priv;
>>  	int ret;
> why not just set the ret = 0 here and save eht work later
>>  
>> +	pm_runtime_get_sync(bus(priv)->dev);
>> +
>>  	IWL_DEBUG_MAC80211(priv, "enter\n");
>>  
>>  	/* we should be verifying the device is ready to be opened */
>> @@ -1762,19 +1765,24 @@ static int iwlagn_mac_start(struct ieee80211_hw *hw)
>>  	ret = __iwl_up(priv);
>>  	mutex_unlock(&priv->shrd->mutex);
>>  	if (ret)
>> -		return ret;
>> +		goto out;
>>  
>>  	IWL_DEBUG_INFO(priv, "Start UP work done.\n");
>>  
>>  	/* Now we should be done, and the READY bit should be set. */
>> -	if (WARN_ON(!test_bit(STATUS_READY, &priv->shrd->status)))
>> +	if (WARN_ON(!test_bit(STATUS_READY, &priv->shrd->status))) {
>>  		ret = -EIO;
>> +		goto out;
>> +	}
>>  
>>  	iwlagn_led_enable(priv);
>>  
>>  	priv->is_open = 1;
>>  	IWL_DEBUG_MAC80211(priv, "leave\n");
>> -	return 0;
>> +	ret = 0;
> if set it earlier, do have to do this
> 
>> +out:
>> +	pm_runtime_put(bus(priv)->dev);
>> +	return ret;
>>  }
>>  
>>  static void iwlagn_mac_stop(struct ieee80211_hw *hw)
>> @@ -1786,6 +1794,8 @@ static void iwlagn_mac_stop(struct ieee80211_hw *hw)
>>  	if (!priv->is_open)
>>  		return;
>>  
>> +	pm_runtime_get_sync(bus(priv)->dev);
>> +
>>  	priv->is_open = 0;
>>  
>>  	iwl_down(priv);
>> @@ -1798,6 +1808,8 @@ static void iwlagn_mac_stop(struct ieee80211_hw *hw)
>>  	iwl_enable_rfkill_int(priv);
>>  
>>  	IWL_DEBUG_MAC80211(priv, "leave\n");
>> +
>> +	pm_runtime_put(bus(priv)->dev);
>>  }
>>  
>>  #ifdef CONFIG_PM_SLEEP
>> diff --git a/drivers/net/wireless/iwlwifi/iwl-pci.c b/drivers/net/wireless/iwlwifi/iwl-pci.c
>> index 1800029..d3f39b2 100644
>> --- a/drivers/net/wireless/iwlwifi/iwl-pci.c
>> +++ b/drivers/net/wireless/iwlwifi/iwl-pci.c
>> @@ -63,6 +63,7 @@
>>  #include <linux/module.h>
>>  #include <linux/pci.h>
>>  #include <linux/pci-aspm.h>
>> +#include <linux/pm_runtime.h>
>>  
>>  #include "iwl-bus.h"
>>  #include "iwl-io.h"
>> @@ -465,6 +466,8 @@ static int iwl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>>  	err = iwl_probe(bus, &trans_ops_pcie, cfg);
>>  	if (err)
>>  		goto out_disable_msi;
>> +
>> +	pm_runtime_put_noidle(&pdev->dev);
>>  	return 0;
>>  
>>  out_disable_msi:
>> @@ -487,6 +490,8 @@ static void __devexit iwl_pci_remove(struct pci_dev *pdev)
>>  	struct pci_dev *pci_dev = IWL_BUS_GET_PCI_DEV(bus);
>>  	struct iwl_shared *shrd = bus->shrd;
>>  
>> +	pm_runtime_get_noresume(&pdev->dev);
>> +
>>  	iwl_remove(shrd->priv);
>>  
>>  	pci_disable_msi(pci_dev);
>> @@ -534,7 +539,21 @@ static int iwl_pci_resume(struct device *device)
>>  	return iwl_trans_resume(shrd->trans);
>>  }
>>  
>> -static SIMPLE_DEV_PM_OPS(iwl_dev_pm_ops, iwl_pci_suspend, iwl_pci_resume);
>> +
>> +static int iwl_pci_runtime_idle(struct device *dev)
>> +{
>> +	struct pci_dev *pdev = to_pci_dev(dev);
>> +	struct iwl_bus *bus = pci_get_drvdata(pdev);
>> +	struct iwl_shared *shrd = bus->shrd;
>> +
>> +	if (!test_bit(STATUS_ALIVE, &shrd->status))
>> +		return 0;
>> +
>> +	return -EBUSY;
>> +}
>> +
>> +static UNIVERSAL_DEV_PM_OPS(iwl_dev_pm_ops, iwl_pci_suspend,
>> +			iwl_pci_resume, iwl_pci_runtime_idle);
>>  
>>  #define IWL_PM_OPS	(&iwl_dev_pm_ops)
>>  
> 
> it looks good, what NIC and system you test with?
Intel Centrino Advanced-N 6230

> also you mention it no longer generate rfkill changes interrupt, could
> you elaborate?
After putting the device into D3hot, the device doesn't generate rfkill
changes interrupt. I also tried check CSR_GP_CNTRL register when the device
is suspended, it doesn't reflect rfkill changes neither.

> 
> btw, could you send the patch to <[email-masked]>
> first if ok for you.
> 
Ok

Regards
Yan, Zheng

> Thanks
> Wey