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From: Vasily Khoruzhick <anarsoul@gmail.com>
To: Torsten Duwe <duwe@lst.de>
Cc: Neil Armstrong <narmstrong@baylibre.com>,
	Robert Foss <robert.foss@linaro.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Thierry Reding <treding@nvidia.com>,
	Lyude Paul <lyude@redhat.com>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Harald Geyer <harald@ccbib.org>,
	stable@vger.kernel.org
Subject: Re: [PATCH] drm/bridge: fix anx6345 power up sequence
Date: Mon, 18 Apr 2022 17:25:57 -0700	[thread overview]
Message-ID: <CA+E=qVdEtx8wVbcrMQYGB1ur1ykvNRp1L174mVSMkB0zeOPYNQ@mail.gmail.com> (raw)
In-Reply-To: <CA+E=qVeX2aU0hiDMxLXzVk-YiMsqKKFKpm=cc=72joMhZmNV1g@mail.gmail.com>

On Sun, Apr 17, 2022 at 11:52 AM Vasily Khoruzhick <anarsoul@gmail.com> wrote:
>
> On Sun, Apr 17, 2022 at 9:15 AM Torsten Duwe <duwe@lst.de> wrote:
> >
> > Align the power-up sequence with the known-good procedure documented in [1]:
> > un-swap dvdd12 and dvdd25, and allow a little extra time for them to settle
> > before de-asserting reset.
>
> Hi Torsten,
>
> Interesting find! I tried to fix the issue several times by playing
> with the delays to no avail.
>
> What's interesting, ANX6345 datasheet allows DVDD12 to come up either
> earlier or later than DVDD25 with the delay of T1 (2ms typical)
> between them, and actually bringing up DVDD12 first works fine in
> u-boot.
>
> The datasheet also requires reset to be deasserted no earlier than T2
> (2-5ms) after all the rails are stable.
>
> Another thing it mentions is that the system clock must be stable for
> T3 (1-3ms) before reset is deasserted, T3 is already a part of T2,
> however it cannot be gated on Pinebook, see [1], page 15
>
> The change looks good to me, but I'll need some time to actually test
> it. If you don't hear from me for longer than a week please ping me.

Your change doesn't fix the issue for me. Running "xrandr --output
eDP-1 --off; xrandr --output eDP-1 --auto" in a loop triggers the
issue pretty quickly even with the patch.

  reply	other threads:[~2022-04-19  0:26 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-17 16:15 [PATCH] drm/bridge: fix anx6345 power up sequence Torsten Duwe
2022-04-17 18:52 ` Vasily Khoruzhick
2022-04-19  0:25   ` Vasily Khoruzhick [this message]
2022-04-28 15:57     ` Torsten Duwe
2022-05-18 16:53       ` Vasily Khoruzhick
2022-05-19 13:39         ` Torsten Duwe
2022-05-21 15:28           ` Vasily Khoruzhick

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