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Message-ID: <227bce07-37cc-da1d-fc99-065a12cdf3f5@collabora.com>
Date:   Mon, 19 Sep 2022 15:32:52 +0200
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Subject: Re: [PATCH] drm/mediatek: dsi: Move mtk_dsi_stop() call back to
 mtk_dsi_poweroff()
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To:     Hsin-Yi Wang <hsinyi@chromium.org>,
        =?UTF-8?B?TsOtY29sYXMgRi4gUi4gQS4gUHJhZG8=?= 
        <nfraprado@collabora.com>
Cc:     Chun-Kuang Hu <chunkuang.hu@kernel.org>, kernel@collabora.com,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@linux.ie>,
        Jitao Shi <jitao.shi@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Rex-BC Chen <rex-bc.chen@mediatek.com>,
        Xinlei Lee <xinlei.lee@mediatek.com>,
        dri-devel@lists.freedesktop.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mediatek@lists.infradead.org
References: <20220804194325.1596554-1-nfraprado@collabora.com>
 <CAJMQK-hOxxvkjgOxA6KLLUJxxBehHDQvRo-Y_FLMPLEfkoVMzA@mail.gmail.com>
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
In-Reply-To: <CAJMQK-hOxxvkjgOxA6KLLUJxxBehHDQvRo-Y_FLMPLEfkoVMzA@mail.gmail.com>
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Il 19/09/22 10:40, Hsin-Yi Wang ha scritto:
> On Mon, Sep 19, 2022 at 4:39 PM Nícolas F. R. A. Prado
> <nfraprado@collabora.com> wrote:
>>
>> As the comment right before the mtk_dsi_stop() call advises,
>> mtk_dsi_stop() should only be called after
>> mtk_drm_crtc_atomic_disable(). That's because that function calls
>> drm_crtc_wait_one_vblank(), which requires the vblank irq to be enabled.
>>
>> Previously mtk_dsi_stop(), being in mtk_dsi_poweroff() and guarded by a
>> refcount, would only be called at the end of
>> mtk_drm_crtc_atomic_disable(), through the call to mtk_crtc_ddp_hw_fini().
>> Commit cde7e2e35c28 ("drm/mediatek: Separate poweron/poweroff from
>> enable/disable and define new funcs") moved the mtk_dsi_stop() call to
>> mtk_output_dsi_disable(), causing it to be called before
>> mtk_drm_crtc_atomic_disable(), and consequently generating vblank
>> timeout warnings during suspend.
>>
>> Move the mtk_dsi_stop() call back to mtk_dsi_poweroff() so that we have
>> a working vblank irq during mtk_drm_crtc_atomic_disable() and stop
>> getting vblank timeout warnings.
>>
>> Fixes: cde7e2e35c28 ("drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs")
>> Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
>>
> Tested-by: Hsin-Yi Wang <hsinyi@chromium.org>
> 

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