Message-ID: <4F324321.7030004@qca.qualcomm.com> (sfid-20120208_104107_731424_AC494A8A)
Date: Wed, 8 Feb 2012 15:10:49 +0530
From: Raja Mani <rmani@qca.qualcomm.com>
MIME-Version: 1.0
To: Kalle Valo <kvalo@qca.qualcomm.com>
CC: <linux-wireless@vger.kernel.org>, <ath6kl-devel@qualcomm.com>
Subject: Re: [PATCH] ath6kl: Check wow state before sending control and data
 pkt
References: <1328536613-17521-1-git-send-email-rmani@qca.qualcomm.com> <4F2FE044.2000106@qca.qualcomm.com> <4F30F980.9010206@qca.qualcomm.com> <4F31280F.9000306@qca.qualcomm.com>
In-Reply-To: <4F31280F.9000306@qca.qualcomm.com>
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Sender: linux-wireless-owner@vger.kernel.org

On Tuesday 07 February 2012 07:03 PM, Kalle Valo wrote:
> On 02/07/2012 12:14 PM, Raja Mani wrote:
>> On Monday 06 February 2012 07:44 PM, Kalle Valo wrote:
>>> On 02/06/2012 03:56 PM, rmani@qca.qualcomm.com wrote:
>>>>
>>>> +enum ath6kl_wow_state {
>>>> +	ATH6KL_WOW_STATE_NONE,
>>>> +	ATH6KL_WOW_STATE_SUSPENDING,
>>>> +	ATH6KL_WOW_STATE_SUSPENDED,
>>>> +};
>>>> +
>>>>    struct ath6kl {
>>>>    	struct device *dev;
>>>>    	struct wiphy *wiphy;
>>>>
>>>>    	enum ath6kl_state state;
>>>> +	enum ath6kl_wow_state wow_state;
>>>>    	unsigned int testmode;
>>>
>>> To be honest, adding a new state variable scares me. I don't see how we
>>> are able to maintain two different state variables, the end result would
>>> be a total mess.
>>
>> ath6kl_wow_state is a just sub state of WOW. It roles over only in WOW
>> mode. However i understand your point.
>
> It's not just a substate as it's separately checked in txrx.c.
>
>>> I recommend to look at this problem by adding a new state to enum
>>> ath6kl_state. That would make it a lot easier to handle all the
>>> different states.
>>
>> The condition to stop ctrl and data pkt transfer are different.
>> Ctrl pkt should be stopped when wow_suspended (after sending
>> set_host_sleep_cmd_mode). Data pkt should be dropped before
>> the moment we configure set_ip_cmd().
>
> Don't think about dropping packets, instead try to make sure that the
> packet flow is _stopped_. Dropping packets should be the last resort,
> instead we need to go to the source of the packets. For data packets
> this means that we need to stop netdev queues. For control packets we
> need to make sure that cfg80211 ops in cfg80211.c don't issue any new
> wmi commands. And maybe we should also consider debugfs and wmi events
> as they can also issue new wmi commands.
>
>> This where we need a state WOW_SUSPENDING and WOW_SUSPENDED.
>> enum ath6kl_state has over all ath6kl suspend state (cut pwr, deep
>> sleep,wow). IMHO, mixing WOW sub states there is not good approach.
>
> How is this problem related only to WoW? Doesn't it apply to all suspend
> modes?
>
>> If you feel maintaining separate state is not good idea, i could think
>> of introducing two new flag WOW_SUSPENDING,  WOW_SUSPENDED in ar->flag.
>
> After a quick thought having a SUSPENDING state makes, but I can't see
> the reason for name WOW_SUSPENDING. WOW_SUSPENDED is unclear for me,
> what's the difference to ATH6KL_STATE_WOW?

Thanks your review. I'll submit V2 by considering all your comments.

>
> Kalle