netdev - RE: [PATCH V7 4/9] wifi: mac80211: Add support for ACPI WBRF

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID:
 <DM6PR12MB26196A993B3BA93392AA0FEDE403A@DM6PR12MB2619.namprd12.prod.outlook.com>
Date: Tue, 25 Jul 2023 10:38:22 +0000
From: "Quan, Evan" <Evan.Quan@....com>
To: "Limonciello, Mario" <Mario.Limonciello@....com>, Andrew Lunn
	<andrew@...n.ch>
CC: "rafael@...nel.org" <rafael@...nel.org>, "lenb@...nel.org"
	<lenb@...nel.org>, "Deucher, Alexander" <Alexander.Deucher@....com>, "Koenig,
 Christian" <Christian.Koenig@....com>, "Pan, Xinhui" <Xinhui.Pan@....com>,
	"airlied@...il.com" <airlied@...il.com>, "daniel@...ll.ch" <daniel@...ll.ch>,
	"johannes@...solutions.net" <johannes@...solutions.net>,
	"davem@...emloft.net" <davem@...emloft.net>, "edumazet@...gle.com"
	<edumazet@...gle.com>, "kuba@...nel.org" <kuba@...nel.org>,
	"pabeni@...hat.com" <pabeni@...hat.com>, "mdaenzer@...hat.com"
	<mdaenzer@...hat.com>, "maarten.lankhorst@...ux.intel.com"
	<maarten.lankhorst@...ux.intel.com>, "tzimmermann@...e.de"
	<tzimmermann@...e.de>, "hdegoede@...hat.com" <hdegoede@...hat.com>,
	"jingyuwang_vip@....com" <jingyuwang_vip@....com>, "Lazar, Lijo"
	<Lijo.Lazar@....com>, "jim.cromie@...il.com" <jim.cromie@...il.com>,
	"bellosilicio@...il.com" <bellosilicio@...il.com>, "andrealmeid@...lia.com"
	<andrealmeid@...lia.com>, "trix@...hat.com" <trix@...hat.com>,
	"jsg@....id.au" <jsg@....id.au>, "arnd@...db.de" <arnd@...db.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH V7 4/9] wifi: mac80211: Add support for ACPI WBRF

[AMD Official Use Only - General]

> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@....com>
> Sent: Monday, July 24, 2023 9:41 PM
> To: Andrew Lunn <andrew@...n.ch>; Quan, Evan <Evan.Quan@....com>
> Cc: rafael@...nel.org; lenb@...nel.org; Deucher, Alexander
> <Alexander.Deucher@....com>; Koenig, Christian
> <Christian.Koenig@....com>; Pan, Xinhui <Xinhui.Pan@....com>;
> airlied@...il.com; daniel@...ll.ch; johannes@...solutions.net;
> davem@...emloft.net; edumazet@...gle.com; kuba@...nel.org;
> pabeni@...hat.com; mdaenzer@...hat.com;
> maarten.lankhorst@...ux.intel.com; tzimmermann@...e.de;
> hdegoede@...hat.com; jingyuwang_vip@....com; Lazar, Lijo
> <Lijo.Lazar@....com>; jim.cromie@...il.com; bellosilicio@...il.com;
> andrealmeid@...lia.com; trix@...hat.com; jsg@....id.au; arnd@...db.de;
> linux-kernel@...r.kernel.org; linux-acpi@...r.kernel.org; amd-
> gfx@...ts.freedesktop.org; dri-devel@...ts.freedesktop.org; linux-
> wireless@...r.kernel.org; netdev@...r.kernel.org
> Subject: Re: [PATCH V7 4/9] wifi: mac80211: Add support for ACPI WBRF
>
> On 7/24/2023 04:22, Andrew Lunn wrote:
> >> @@ -1395,6 +1395,8 @@ int ieee80211_register_hw(struct
> ieee80211_hw *hw)
> >>    debugfs_hw_add(local);
> >>    rate_control_add_debugfs(local);
> >>
> >> +  ieee80211_check_wbrf_support(local);
> >> +
> >>    rtnl_lock();
> >>    wiphy_lock(hw->wiphy);
> >>
> >
> >> +void ieee80211_check_wbrf_support(struct ieee80211_local *local) {
> >> +  struct wiphy *wiphy = local->hw.wiphy;
> >> +  struct device *dev;
> >> +
> >> +  if (!wiphy)
> >> +          return;
> >> +
> >> +  dev = wiphy->dev.parent;
> >> +  if (!dev)
> >> +          return;
> >> +
> >> +  local->wbrf_supported = wbrf_supported_producer(dev);
> >> +  dev_dbg(dev, "WBRF is %s supported\n",
> >> +          local->wbrf_supported ? "" : "not"); }
> >
> > This seems wrong. wbrf_supported_producer() is about "Should this
> > device report the frequencies it is using?" The answer to that depends
> > on a combination of: Are there consumers registered with the core, and
> > is the policy set so WBRF should take actions. > The problem here is,
> > you have no idea of the probe order. It could be this device probes
> > before others, so wbrf_supported_producer() reports false, but a few
> > second later would report true, once other devices have probed.
> >
> > It should be an inexpensive call into the core, so can be made every
> > time the channel changes. All the core needs to do is check if the
> > list of consumers is empty, and if not, check a Boolean policy value.
> >
> >       Andrew
>
> No, it's not a combination of whether consumers are registered with the core.
> If a consumer probes later it needs to know the current in use frequencies too.
>
> The reason is because of this sequence of events:
> 1) Producer probes.
> 2) Producer selects a frequency.
> 3) Consumer probes.
> 4) Producer stays at same frequency.
>
> If the producer doesn't notify the frequency because a consumer isn't yet
> loaded then the consumer won't be able to get the current frequency.
Yes, exactly.