Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <fd660017-b502-f72d-c1d7-f94170057fc6@collabora.com>
Date:   Wed, 4 Jan 2023 10:23:39 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.6.0
Subject: Re: [PATCH] remoteproc/mtk_scp: Move clk ops outside send_lock
To:     Chen-Yu Tsai <wenst@chromium.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Matthias Brugger <matthias.bgg@gmail.com>
Cc:     linux-remoteproc@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        Tinghan Shen <tinghan.shen@mediatek.com>,
        Tzung-Bi Shih <tzungbi@kernel.org>,
        Allen-KH Cheng <allen-kh.cheng@mediatek.com>
References: <20230104083110.736377-1-wenst@chromium.org>
Content-Language: en-US
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <20230104083110.736377-1-wenst@chromium.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

Il 04/01/23 09:31, Chen-Yu Tsai ha scritto:
> Clocks are properly reference counted and do not need to be inside the
> lock range.
> 
> Right now this triggers a false-positive lockdep warning on MT8192 based
> Chromebooks, through a combination of mtk-scp that has a cros-ec-rpmsg
> sub-device, the (actual) cros-ec I2C adapter registration, I2C client
> (not on cros-ec) probe doing i2c transfers and enabling clocks.
> 
> This is a false positive because the cros-ec-rpmsg under mtk-scp does
> not have an I2C adapter, and also each I2C adapter and cros-ec instance
> have their own mutex.
> 
> Move the clk operations outside of the send_lock range.
> 
> Fixes: ("63c13d61eafe remoteproc/mediatek: add SCP support for mt8183")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>

Nice catch.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>