linux-kernel - Re: [PATCH 2/2] drivers: qcom: rpmh-rsc: fix read back of trigger register

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Message-ID: <5d320a79.1c69fb81.17c57.b9ba@mx.google.com>
Date:   Fri, 19 Jul 2019 11:22:48 -0700
From:   Stephen Boyd <swboyd@...omium.org>
To:     Lina Iyer <ilina@...eaurora.org>, andy.gross@...aro.org,
        bjorn.andersson@...aro.org
Cc:     linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        rnayak@...eaurora.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, dianders@...omium.org,
        mkshah@...eaurora.org, Lina Iyer <ilina@...eaurora.org>
Subject: Re: [PATCH 2/2] drivers: qcom: rpmh-rsc: fix read back of trigger register

Quoting Lina Iyer (2019-07-01 08:29:07)
> When triggering a TCS to send its contents, reading back the trigger
> value may return an incorrect value. That is because, writing the
> trigger may raise an interrupt which could be handled immediately and
> the trigger value could be reset in the interrupt handler. By doing a
> read back we may end up spinning waiting for the value we wrote.

Doesn't this need to be squashed into the patch that gets rid of the
irqs disabled state of this code? It sounds an awful lot like this
problem only happens now because the previous patch removed the
irqsave/irqrestore code around this function.