From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Priit Laes <plaes@plaes.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-sunxi@googlegroups.com, Chen-Yu Tsai <wens@csie.org>,
Jonathan Liu <net147@gmail.com>,
dri-devel@lists.freedesktop.org
Subject: Re: [linux-sunxi] Re: HDMI/DVI spurious failure
Date: Wed, 16 Jan 2019 20:24:42 +0100 [thread overview]
Message-ID: <20190116192442.qz4xi2ky6axgiyvg@flea> (raw)
In-Reply-To: <20190116075854.o2kme5nxq5kckwem@plaes.org>
Hi Priit,
On Wed, Jan 16, 2019 at 07:58:54AM +0000, Priit Laes wrote:
> > On Mon, Jan 14, 2019 at 01:29:34PM +0000, Priit Laes wrote:
> > > I have a somewhat curious case with one HDMI/DVI screen that fails
> > > to initialize properly every 6-7 boots. The display itself is also
> > > somewhat flawed (missing HPD pin and the VSYNC/HSYNC pulse width
> > > is set to 0 in EDID), but I suspect there could be some issues
> > > regarding timing in A20 HDMI driver in Linux.
> > >
> ...
>
> > It doesn't look related to the clock rate itself, since it doesn't
> > change between the two cases. However, in one case the DDC clock is
> > enabled and in the other it's disabled.
> >
> > Was it taken at the same time? Maybe you can try with that patch?
> > http://code.bulix.org/z7jmkm-555344?raw
>
> Thanks, after doing ~50+ boots I haven't seen a single failure.
>
> Previously I had following failure cases which are now both fixed:
>
> a) Linux without u-boot HDMI, where one in every 6-7 boots failed.
> b) u--boot with hdmi enabled switching to simplefb and then switching
> to kms, where previously all boots ended up with garbled screen.
So it's not really a fix, but it really looks like the clock is not
enabled when it should.
Can you describe your test scenario a bit more? What are you doing
exactly, just booting? When do you start using the display? When did
you capture the debugfs output that you pasted?
Thanks!
Maxime
--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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next prev parent reply other threads:[~2019-01-16 19:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190114132934.rywqqtjarbf6fgcr@plaes.org>
2019-01-15 9:49 ` HDMI/DVI spurious failure Maxime Ripard
2019-01-16 7:58 ` [linux-sunxi] " Priit Laes
2019-01-16 19:24 ` Maxime Ripard [this message]
2019-01-16 20:35 ` Priit Laes
2019-01-17 11:33 ` Maxime Ripard
2019-01-18 10:10 ` Priit Laes
2019-01-18 14:04 ` Maxime Ripard
2019-01-18 14:51 ` Priit Laes
2019-01-21 13:25 ` Maxime Ripard
2019-01-21 15:07 ` Priit Laes
2019-01-21 17:18 ` Jernej Škrabec
2019-01-21 17:20 ` Chen-Yu Tsai
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