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From:   Chun-Kuang Hu <chunkuang.hu@kernel.org>
Date:   Mon, 3 Aug 2020 07:38:15 +0800
Message-ID: <CAAOTY_9PZQLNFNfOPVL-YnvPNG6WjY7pcwK+wO0vEFkR=19txA@mail.gmail.com>
Subject: Re: [PATCH v2 2/5] drm/mediatek: fix boot up for 720 and 480 but 1080
To:     Frank Wunderlich <frank-w@public-files.de>
Cc:     "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        Chun-Kuang Hu <chunkuang.hu@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        chunhui dai <chunhui.dai@mediatek.com>,
        David Airlie <airlied@linux.ie>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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Hi, Frank:

Frank Wunderlich <frank-w@public-files.de> =E6=96=BC 2020=E5=B9=B48=E6=9C=
=882=E6=97=A5 =E9=80=B1=E6=97=A5 =E4=B8=8B=E5=8D=8812:44=E5=AF=AB=E9=81=93=
=EF=BC=9A
>
> Hi,
>
> Am 2. August 2020 02:08:44 MESZ schrieb Chun-Kuang Hu <chunkuang.hu@kerne=
l.org>:
> >Hi, Frank:
> >> - disable tmds on phy on mt2701
> >> - support other resolutions like 1280x1024
> >
> >If this patch does two things, it should be broken into two patches.
> As far as i see,it only disable tmds and so fix specific resolutions like=
 the the one below.some other (like 1080p) does not have this Problem.

OK, this is one thing, "disable tmds on phy on mt2701 to support other
resolutions like 1280x1024"

>
> > I think every pll is default off, so you should turn on pll rather
> > than disable tmds
>
> Is disabling tmds wrong here? Which pll is needed here? What does tmds? I=
 got only the Patches for testing....

I don't know how does this pll and tmds work. I think you and me are
both not familiar with this hdmi phy. I agree this modification could
fix some problem, but does this patch have side effect which trigger
another problem? I need some reasonable description so I could have
confidence on this patch. tmds is a function in mt2701 but you disable
it. This mean you disable some function of this hardware. Why mt2701
does not need it?

Regards,
Chun-Kuang.

>
> >> without this Patch i see flickering on my TFT (1280x1024),
> >> so i guess clock is wrong.
>
> regards Frank