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: <0bf7b7d5-087b-912e-412e-2b3b742448bd@mediatek.com>
Date:   Wed, 21 Sep 2022 16:49:24 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.9.1
Subject: Re: [PATCH] drm/mediatek: dsi: Move mtk_dsi_stop() call back to
 mtk_dsi_poweroff()
Content-Language: en-US
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        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>
 <227bce07-37cc-da1d-fc99-065a12cdf3f5@collabora.com>
From:   Allen-KH Cheng <allen-kh.cheng@mediatek.com>
In-Reply-To: <227bce07-37cc-da1d-fc99-065a12cdf3f5@collabora.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit
Precedence: bulk


On 9/19/22 21:32, AngeloGioacchino Del Regno wrote:
> 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>
> 
> 

Tested suspend/resume work properly on mt8188 and mt8186  .

Tested-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>