From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 2/2] drm: bridge/dw_hdmi: add dw hdmi i2c bus adapter support
Date: Wed, 16 Sep 2015 23:18:19 +0100 [thread overview]
Message-ID: <20150916221819.GJ21084@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <CAD=FV=Vk+qziHohVL_Zaag0qqh_R6DnA1s-ppVFC=cBccAn4EA@mail.gmail.com>
On Wed, Sep 16, 2015 at 02:56:57PM -0700, Doug Anderson wrote:
> Yes, I'd expect 100kHz and 400kHz.
>
> I agree that 50ms is non-trivial, but it's also not something you're
> doing lots of. I'd expect that the EDID is read over this channel at
> cable plugin time and then not used much after that. Adding an extra
> 40ms (10ms vs 50ms) before we can access the TV doesn't seem terrible
> for compatibility.
>
> Doing a quick scan for what others in mainline do:
>
> A few can be found with:
>
> $ git grep -A3 hdmiddc | grep clock-freq
> arch/arm/boot/dts/stihxxx-b2120.dtsi-
> clock-frequency = <100000>;
> arch/arm/boot/dts/tegra30-apalis.dtsi- clock-frequency = <100000>;
> arch/arm/boot/dts/tegra30-beaver.dts- clock-frequency = <100000>;
> arch/arm/boot/dts/tegra30-colibri.dtsi- clock-frequency = <100000>;
This is a sure way to propagate a bug.
I said in a previous email that you need to check the HDMI and CEA
specs. I've done this, and HDMI 1.3a specifies a maximum SCL clock
rate of 100kHz.
So that's settled then. 100kHz is must be. Using 400kHz is out of
specification.
--
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2015-09-16 22:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-30 21:34 [PATCH v3 2/2] drm: bridge/dw_hdmi: add dw hdmi i2c bus adapter support Vladimir Zapolskiy
2015-08-31 9:22 ` Philipp Zabel
2015-09-02 22:07 ` Doug Anderson
2015-09-02 22:50 ` Russell King - ARM Linux
2015-09-02 23:00 ` Doug Anderson
2015-09-02 23:04 ` Russell King - ARM Linux
2015-09-02 23:19 ` Doug Anderson
2015-09-16 21:16 ` Vladimir Zapolskiy
2015-09-16 22:02 ` Doug Anderson
2015-09-02 23:43 ` Doug Anderson
2015-09-03 9:19 ` Russell King - ARM Linux
2015-09-03 9:39 ` Thierry Reding
2015-09-03 16:08 ` Doug Anderson
2015-09-08 22:08 ` Wolfram Sang
2015-09-16 20:04 ` Doug Anderson
2015-09-16 20:58 ` Vladimir Zapolskiy
2015-09-16 21:56 ` Doug Anderson
2015-09-16 22:18 ` Russell King - ARM Linux [this message]
2015-09-21 14:00 ` Vladimir Zapolskiy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150916221819.GJ21084@n2100.arm.linux.org.uk \
--to=linux@arm.linux.org.uk \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).