linux-kernel - Re: [PATCH v2] drm: mediatek: Fix display vblank timeout when disable dsi

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Date:   Tue, 20 Sep 2022 11:47:53 +0800
From:   Allen-KH Cheng <allen-kh.cheng@...iatek.com>
To:     Chun-Kuang Hu <chunkuang.hu@...nel.org>
CC:     Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Matthias Brugger <matthias.bgg@...il.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Project_Global_Chrome_Upstream_Group 
        <Project_Global_Chrome_Upstream_Group@...iatek.com>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        Xinlei Lee (李昕磊) 
        <Xinlei.Lee@...iatek.com>
Subject: Re: [PATCH v2] drm: mediatek: Fix display vblank timeout when disable
 dsi

Hi CK,

We can use [1] in mt8186. Please ignore this PATCH.

Thanks,
Allen

[1]
http://lists.infradead.org/pipermail/linux-mediatek/2022-August/046713.html

On 9/19/22 11:01, Allen-KH Cheng wrote:
> Hi CK,
> 
> We will test this fix on the mt8186/mt8183.
> Maybe our fix is not necessary.
> 
> I appreciate your suggestion.
> 
> BRs,
> Allen
> 
> On 9/18/22 12:32, Chun-Kuang Hu wrote:
>> Hi, Allen:
>>
>> Allen-KH Cheng <allen-kh.cheng@...iatek.com> 於 2022年9月14日 週三 晚上10:00寫道：
>>>
>>> From: Xinlei Lee <xinlei.lee@...iatek.com>
>>>
>>> Dsi is turned off at bridge.disable, causing crtc to wait for vblank
>>> timeout. It is necessary to add count protection to turn off dsi and
>>> turn off at post_disable.
>>
>> If turn off dsi in post_disable(), you should turn on dsi in pre_enable().
>>
>> There is another patch fix this problem [1], do you have any comment
>> on that patch?
>>
>> [1] http://lists.infradead.org/pipermail/linux-mediatek/2022-August/046713.html
>>
>> Regards,
>> Chun-Kuang.
>>
>>>
>>> Fixes: cde7e2e35c28 ("drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs")
>>> Signed-off-by: Xinlei Lee <xinlei.lee@...iatek.com>
>>> Co-developed-by: Allen-KH Cheng <allen-kh.cheng@...iatek.com>
>>> Signed-off-by: Allen-KH Cheng <allen-kh.cheng@...iatek.com>
>>> ---
>>> Change in v1:
>>>   * Rebase to kernel/git/chunkuang.hu/linux.git, mediatek-drm-fixes
>>>     [Allen-KH Cheng <allen-kh.cheng@...iatek.com>]
>>> ---
>>> ---
>>>  drivers/gpu/drm/mediatek/mtk_dsi.c | 15 ++++++---------
>>>  1 file changed, 6 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> index 5b624e0f5b0a..e30f4244c001 100644
>>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
>>> @@ -768,14 +768,6 @@ static void mtk_dsi_bridge_mode_set(struct drm_bridge *bridge,
>>>         drm_display_mode_to_videomode(adjusted, &dsi->vm);
>>>  }
>>>
>>> -static void mtk_dsi_bridge_atomic_disable(struct drm_bridge *bridge,
>>> -                                         struct drm_bridge_state *old_bridge_state)
>>> -{
>>> -       struct mtk_dsi *dsi = bridge_to_dsi(bridge);
>>> -
>>> -       mtk_output_dsi_disable(dsi);
>>> -}
>>> -
>>>  static void mtk_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
>>>                                          struct drm_bridge_state *old_bridge_state)
>>>  {
>>> @@ -803,13 +795,15 @@ static void mtk_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge,
>>>  {
>>>         struct mtk_dsi *dsi = bridge_to_dsi(bridge);
>>>
>>> +       if (dsi->refcount == 1)
>>> +               mtk_output_dsi_disable(dsi);
>>> +
>>>         mtk_dsi_poweroff(dsi);
>>>  }
>>>
>>>  static const struct drm_bridge_funcs mtk_dsi_bridge_funcs = {
>>>         .attach = mtk_dsi_bridge_attach,
>>>         .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
>>> -       .atomic_disable = mtk_dsi_bridge_atomic_disable,
>>>         .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
>>>         .atomic_enable = mtk_dsi_bridge_atomic_enable,
>>>         .atomic_pre_enable = mtk_dsi_bridge_atomic_pre_enable,
>>> @@ -829,6 +823,9 @@ void mtk_dsi_ddp_stop(struct device *dev)
>>>  {
>>>         struct mtk_dsi *dsi = dev_get_drvdata(dev);
>>>
>>> +       if (dsi->refcount == 1)
>>> +               mtk_output_dsi_disable(dsi);
>>> +
>>>         mtk_dsi_poweroff(dsi);
>>>  }
>>>
>>> --
>>> 2.18.0
>>>