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From:   Vasily Khoruzhick <anarsoul@gmail.com>
Date:   Thu, 16 May 2019 11:26:45 -0700
Message-ID: <CA+E=qVdxvU5t9MB447Zd+-MO7rw+qBxxaZApjp4fgDx=W47r-g@mail.gmail.com>
Subject: Re: [PATCH 4/4] arm64: DTS: allwinner: a64: enable ANX6345 bridge on Teres-I
To:     Torsten Duwe <duwe@lst.de>
Cc:     David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Andrzej Hajda <a.hajda@samsung.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Icenowy Zheng <icenowy@aosc.io>,
        Sean Paul <seanpaul@chromium.org>,
        Harald Geyer <harald@ccbib.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        devicetree <devicetree@vger.kernel.org>,
        arm-linux <linux-arm-kernel@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Thu, May 16, 2019 at 9:49 AM Torsten Duwe <duwe@lst.de> wrote:
>
> On Thu, May 16, 2019 at 09:06:41AM -0700, Vasily Khoruzhick wrote:
> >
> > Driver can talk to the panel over AUX channel only after t1+t3, t1 is
> > up to 10ms, t3 is up to 200ms.
>
> This is after power-on. The boot loader needs to deal with this.

Actually panel driver has to deal with it and not bootloader.

> > It works with older version of driver
> > that keeps panel always on because it takes a while between driver
> > probe and pipeline start.
>
> No lid switch, no USB, no WiFi, no MMC. If you disable DCDC1 you'll
> run out of wakeup-sources ;-) IOW: I see no practical way any OS
> driver can switch this panel voltage off and survive...

Ouch, looks like someone made a huge mistake in HW design?

> > All in all - you don't need panel timings since there's EDID but you
> > still need panel delays. Anyway, it's up to you and maintainers.
>
> Let's give it a try.
>
>         Torsten
>