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Message-ID: <20110209195815.GB2192@tux> Date: Wed, 9 Feb 2011 11:58:15 -0800 From: "Luis R. Rodriguez" <lrodriguez@...eros.com> To: Mohammed Shajakhan <Mohammed.Shajakhan@...eros.com> CC: "linville@...driver.com" <linville@...driver.com>, "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>, Luis Rodriguez <Luis.Rodriguez@...eros.com>, <linux-kernel@...r.kernel.org>, <netdev@...r.kernel.org>, Tim Gardner <tim.gardner@...onical.com>, Mark Gross <mgross@...ux.intel.com> Subject: Re: [RFC] ath9k: Fix ath9k prevents CPU to enter C3 states On Wed, Feb 09, 2011 at 06:33:27AM -0800, Mohammed Shajakhan wrote: > From: Mohammed Shafi Shajakhan <mshajakhan@...eros.com> > > The DMA latency issue is observed only in Intel pinetrail platforms but > in the driver we had a default PM-QOS value of 55. This caused > unnecessary power consumption and battery drain in other platforms. > Address this issue by disabling PM-QOS by default by setting it's value > as '0' and making code changes appropriately.This addresses the bug: > https://bugzilla.kernel.org/show_bug.cgi?id=27532 > If the user sees some DMA latency issue he can still use the pmqos as a > module parameter to trade power for throughput as below: > sudo modprobe ath9k pmqos=55 How many times are we going to write some work around for some platform unpatched BIOS bug ? mcgrof@tux ~/wireless-testing (git::master)$ git grep pm_qos_update_request drivers/ drivers/net/e1000e/netdev.c: pm_qos_update_request(&adapter->netdev->pm_qos_req, 55); drivers/net/e1000e/netdev.c: pm_qos_update_request(&adapter->netdev->pm_qos_req, drivers/net/wireless/ath/ath9k/main.c: pm_qos_update_request(&sc->pm_qos_req, ath9k_pm_qos_value); drivers/net/wireless/ath/ath9k/main.c: pm_qos_update_request(&sc->pm_qos_req, PM_QOS_DEFAULT_VALUE); drivers/net/wireless/ipw2x00/ipw2100.c: pm_qos_update_request(&ipw2100_pm_qos_req, 175); drivers/net/wireless/ipw2x00/ipw2100.c: pm_qos_update_request(&ipw2100_pm_qos_req, PM_QOS_DEFAULT_VALUE); Can't we punt this crap to userspace? http://www.kernel.org/pub/linux/kernel/people/mcgrof/scripts/cpudmalatency.c Can distributions just autodetect this issue and call something like this? Luis > Signed-off-by: Mohammed Shafi Shajakhan <mshajakhan@...eros.com> > --- > drivers/net/wireless/ath/ath9k/ath9k.h | 4 +++- > drivers/net/wireless/ath/ath9k/init.c | 9 +++++---- > drivers/net/wireless/ath/ath9k/main.c | 9 +++++---- > 3 files changed, 13 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h > index 9272278..55fcd01 100644 > --- a/drivers/net/wireless/ath/ath9k/ath9k.h > +++ b/drivers/net/wireless/ath/ath9k/ath9k.h > @@ -57,7 +57,9 @@ struct ath_node; > > #define A_MAX(a, b) ((a) > (b) ? (a) : (b)) > > -#define ATH9K_PM_QOS_DEFAULT_VALUE 55 > +/* By default PM QOS is disabled */ > +#define ATH9K_PM_QOS_DEFAULT_VALUE 0 > + > > #define TSF_TO_TU(_h,_l) \ > ((((u32)(_h)) << 22) | (((u32)(_l)) >> 10)) > diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c > index e5c1eea..658ea02 100644 > --- a/drivers/net/wireless/ath/ath9k/init.c > +++ b/drivers/net/wireless/ath/ath9k/init.c > @@ -43,7 +43,7 @@ MODULE_PARM_DESC(btcoex_enable, "Enable wifi-BT coexistence"); > > int ath9k_pm_qos_value = ATH9K_PM_QOS_DEFAULT_VALUE; > module_param_named(pmqos, ath9k_pm_qos_value, int, S_IRUSR | S_IRGRP | S_IROTH); > -MODULE_PARM_DESC(pmqos, "User specified PM-QOS value"); > +MODULE_PARM_DESC(pmqos, "User specified PM-QOS value, by default disabled"); > > bool is_ath9k_unloaded; > /* We use the hw_value as an index into our private channel structure */ > @@ -759,8 +759,8 @@ int ath9k_init_device(u16 devid, struct ath_softc *sc, u16 subsysid, > > ath_init_leds(sc); > ath_start_rfkill_poll(sc); > - > - pm_qos_add_request(&sc->pm_qos_req, PM_QOS_CPU_DMA_LATENCY, > + if (ath9k_pm_qos_value) > + pm_qos_add_request(&sc->pm_qos_req, PM_QOS_CPU_DMA_LATENCY, > PM_QOS_DEFAULT_VALUE); > > return 0; > @@ -819,7 +819,8 @@ void ath9k_deinit_device(struct ath_softc *sc) > ath9k_ps_restore(sc); > > ieee80211_unregister_hw(hw); > - pm_qos_remove_request(&sc->pm_qos_req); > + if (ath9k_pm_qos_value) > + pm_qos_remove_request(&sc->pm_qos_req); > ath_rx_cleanup(sc); > ath_tx_cleanup(sc); > ath9k_deinit_softc(sc); > diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c > index 4ed43b2..3855092 100644 > --- a/drivers/net/wireless/ath/ath9k/main.c > +++ b/drivers/net/wireless/ath/ath9k/main.c > @@ -1119,9 +1119,10 @@ static int ath9k_start(struct ieee80211_hw *hw) > > /* User has the option to provide pm-qos value as a module > * parameter rather than using the default value of > - * 'ATH9K_PM_QOS_DEFAULT_VALUE'. > + * 'ATH9K_PM_QOS_DEFAULT_VALUE' which disables PM QOS. > */ > - pm_qos_update_request(&sc->pm_qos_req, ath9k_pm_qos_value); > + if (ath9k_pm_qos_value) > + pm_qos_update_request(&sc->pm_qos_req, ath9k_pm_qos_value); > > if (ah->caps.pcie_lcr_extsync_en && common->bus_ops->extn_synch_en) > common->bus_ops->extn_synch_en(common); > @@ -1266,8 +1267,8 @@ static void ath9k_stop(struct ieee80211_hw *hw) > ath_radio_disable(sc, hw); > > sc->sc_flags |= SC_OP_INVALID; > - > - pm_qos_update_request(&sc->pm_qos_req, PM_QOS_DEFAULT_VALUE); > + if (ath9k_pm_qos_value) > + pm_qos_update_request(&sc->pm_qos_req, PM_QOS_DEFAULT_VALUE); > > mutex_unlock(&sc->mutex); > > -- > 1.7.0.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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