From: "Luis R. Rodriguez" <lrodriguez@atheros.com>
To: Mohammed Shajakhan <Mohammed.Shajakhan@Atheros.com>
Cc: "linville@tuxdriver.com" <linville@tuxdriver.com>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
Luis Rodriguez <Luis.Rodriguez@Atheros.com>,
<linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
Tim Gardner <tim.gardner@canonical.com>,
Mark Gross <mgross@linux.intel.com>
Subject: Re: [RFC] ath9k: Fix ath9k prevents CPU to enter C3 states
Date: Wed, 9 Feb 2011 11:58:15 -0800 [thread overview]
Message-ID: <20110209195815.GB2192@tux> (raw)
In-Reply-To: <1297262007-15128-1-git-send-email-mshajakhan@atheros.com>
On Wed, Feb 09, 2011 at 06:33:27AM -0800, Mohammed Shajakhan wrote:
> From: Mohammed Shafi Shajakhan <mshajakhan@atheros.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@atheros.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
>
next parent reply other threads:[~2011-02-09 19:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1297262007-15128-1-git-send-email-mshajakhan@atheros.com>
2011-02-09 19:58 ` Luis R. Rodriguez [this message]
2011-02-10 14:18 ` [RFC] ath9k: Fix ath9k prevents CPU to enter C3 states Mohammed Shafi
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