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Date:   Tue, 06 Oct 2020 09:15:32 +0000
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From:   kl@kl.wtf
Message-ID: <0ec848359962ebce267168618b816bb4@kl.wtf>
Subject: Re: [PATCH] Input: evdev - per-client waitgroups
To:     dmitry.torokhov@gmail.com
Cc:     linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
In-Reply-To: <20201005233500.GM1009802@dtor-ws>
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 <20200429184126.2155-1-kl@kl.wtf>
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October 6, 2020 1:35 AM, dmitry.torokhov@gmail.com wrote:=0A=0A> On Wed, =
Apr 29, 2020 at 08:41:26PM +0200, Kenny Levinsen wrote:=0A> =0A>> All evd=
ev clients share a common waitgroup. On new input events, this=0A>> waitg=
roup is woken once for every client that did not filter the events,=0A> =
=0A> I am having trouble parsing the changelog (I think I agree with the=
=0A> change itself). Did you mean to say "this waitqueue wakes up every=
=0A> client, even ones that requested to filter out events that are being=
=0A> delivered, leading to duplicated and unwanted wakeups"?=0A=0AAh, I s=
uppose my original wording was a bit convoluted. Perhaps the following=0A=
is clearer:=0A=0A	All evdev clients share a common waitgroup. On new inpu=
t events, all=0A	clients waiting on this waitgroup are woken up, even tho=
se filtering=0A	out the events, possibly more than once per event. This l=
eads to=0A	duplicated and unwanted wakeups.=0A=0AWhat I tried to say is t=
hat not only do all clients polling the device/blocked=0Aon read end up w=
oken up, instead of being woken just once, they are woken once=0Afor ever=
y client that was interested in the event.=0A=0ASo, if you have two clien=
ts interested and one uninterested, then the shared=0Awaitgroup that all =
three clients are waiting on is woken up twice in a row.=0A=0AShould I se=
nd an updated patch with the new wording? I'm also fine with your=0Asugge=
sted wording if you prefer that.=0A=0ABest regards,=0AKenny Levinsen