From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
dri-devel@lists.freedesktop.org,
Andy Yan <andy.yan@rock-chips.com>,
Archit Taneja <architt@codeaurora.org>,
Fabio Estevam <fabio.estevam@freescale.com>,
Heiko Stuebner <heiko@sntech.de>,
Jose Abreu <Jose.Abreu@synopsys.com>,
Kieran Bingham <kieran.bingham@ideasonboard.com>,
Mark Yao <mark.yao@rock-chips.com>,
Philipp Zabel <p.zabel@pengutronix.de>,
Ulrich Hecht <ulrich.hecht@gmail.com>,
Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>,
linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH 13/22] drm: bridge: dw-hdmi: Replace device type with platform quirks
Date: Fri, 2 Dec 2016 16:08:17 +0000 [thread overview]
Message-ID: <20161202160817.GE14217@n2100.armlinux.org.uk> (raw)
In-Reply-To: <4921806.T6YjZHsEAd@avalon>
On Fri, Dec 02, 2016 at 05:43:43PM +0200, Laurent Pinchart wrote:
> DW_HDMI_QUIRK_FC_INVIDCONF is indeed a bad name, I'll fix that.
>
> Do you know why this function needs to write to the HDMI_FC_INVIDCONF
> register four times in the normal case, and once only for IMX6DL ?
(I don't have much time at present, I'm buried in ARM64 crud trying to
get a platform to boot, and working out how to debug an ARM64 platform
that even earlycon doesn't work on... no printascii() types of easy
debug facilities on ARM64 make this job several orders of magnitude
harder than it needs to be...)
It prevents a magenta line down the left hand side of the screen, which
is caused when the frame composer in the HDMI Tx gets confused -
according to the errata, it does a load of maths when you write to the
frame composer registers, and sometimes it doesn't update properly.
So, the four writes (and the number is critical) is there to persuade
the IP to do the maths with the right values so the internal timings
are correct.
The rather confusing thing is - it's actually IMX6Q which has the more
severe errata, not IMX6DL - the workaround of four writes is applied
in the 6Q case.
It's covered by ERR004308 in the IMX6Q Errata document (search for
IMX6DQCE). It isn't mentioned in the IMX6DL documentation, but it
seems that similar workaround of one write is necessary there.
Some of this was determined by experimentation in conjunction with the
errata documentation - I remember it took a while to get it right so
that we didn't ever see the magenta line.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2016-12-02 16:08 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-01 23:43 [PATCH 00/22] R-Car Gen3 HDMI output support Laurent Pinchart
2016-12-01 23:43 ` Laurent Pinchart
2016-12-01 23:43 ` [PATCH 01/22] drm: bridge: dw-hdmi: Merge __hdmi_phy_i2c_write and hdmi_phy_i2c_write Laurent Pinchart
2016-12-01 23:43 ` [PATCH 02/22] drm: bridge: dw-hdmi: Remove unneeded arguments to bind/unbind functions Laurent Pinchart
2016-12-01 23:43 ` [PATCH 03/22] drm: bridge: dw-hdmi: Remove unused function parameter Laurent Pinchart
2016-12-01 23:43 ` Laurent Pinchart
2016-12-01 23:43 ` [PATCH 04/22] drm: bridge: dw-hdmi: Embed drm_bridge in struct dw_hdmi Laurent Pinchart
2016-12-01 23:43 ` [PATCH 05/22] drm: bridge: dw-hdmi: Remove encoder field from " Laurent Pinchart
2016-12-01 23:43 ` [PATCH 06/22] drm: bridge: dw-hdmi: Don't forward HPD events to DRM core before attach Laurent Pinchart
2016-12-01 23:43 ` [PATCH 07/22] drm: bridge: dw-hdmi: Move IRQ and IO resource allocation to common code Laurent Pinchart
2016-12-01 23:43 ` [PATCH 08/22] drm: bridge: dw-hdmi: Reorder functions to prepare for next commit Laurent Pinchart
2016-12-01 23:43 ` [PATCH 09/22] drm: bridge: dw-hdmi: Create connector in the bridge attach operation Laurent Pinchart
2016-12-01 23:43 ` [PATCH 10/22] drm: bridge: dw-hdmi: Implement DRM bridge registration Laurent Pinchart
2016-12-01 23:43 ` [PATCH 11/22] drm: bridge: dw-hdmi: Refactor hdmi_phy_configure resolution parameter Laurent Pinchart
2016-12-02 14:18 ` Russell King - ARM Linux
2016-12-02 15:51 ` Laurent Pinchart
2016-12-02 15:51 ` Laurent Pinchart
2016-12-02 16:08 ` Russell King - ARM Linux
2016-12-05 7:53 ` Kieran Bingham
2016-12-05 7:53 ` Kieran Bingham
2016-12-01 23:43 ` [PATCH 12/22] drm: bridge: dw-hdmi: Abstract the platform PHY configuration Laurent Pinchart
2016-12-02 11:15 ` Jose Abreu
2016-12-02 11:15 ` Jose Abreu
2016-12-02 14:09 ` Laurent Pinchart
2016-12-02 14:09 ` Laurent Pinchart
2016-12-01 23:43 ` [PATCH 13/22] drm: bridge: dw-hdmi: Replace device type with platform quirks Laurent Pinchart
2016-12-02 14:24 ` Russell King - ARM Linux
2016-12-02 15:43 ` Laurent Pinchart
2016-12-02 15:43 ` Laurent Pinchart
2016-12-02 16:08 ` Russell King - ARM Linux [this message]
2016-12-02 16:45 ` Laurent Pinchart
2016-12-02 16:45 ` Laurent Pinchart
2016-12-05 11:51 ` Laurent Pinchart
2016-12-05 11:51 ` Laurent Pinchart
2016-12-05 10:50 ` Jose Abreu
2016-12-05 10:50 ` Jose Abreu
2016-12-05 11:32 ` Laurent Pinchart
2016-12-05 11:32 ` Laurent Pinchart
2016-12-05 12:31 ` Jose Abreu
2016-12-05 12:31 ` Jose Abreu
2016-12-05 12:44 ` Laurent Pinchart
2016-12-05 12:44 ` Laurent Pinchart
2016-12-01 23:43 ` [PATCH 14/22] dt-bindings: display: dw-hdmi: Clean up DT bindings documentation Laurent Pinchart
2016-12-06 21:15 ` Rob Herring
2016-12-06 21:15 ` Rob Herring
2016-12-07 9:53 ` Laurent Pinchart
2016-12-07 9:53 ` Laurent Pinchart
[not found] ` <1480635817-1258-1-git-send-email-laurent.pinchart+renesas-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org>
2016-12-01 23:43 ` [PATCH 15/22] dt-bindings: display: renesas: Add R-Car Gen3 HDMI TX DT bindings Laurent Pinchart
2016-12-01 23:43 ` Laurent Pinchart
2016-12-06 21:18 ` Rob Herring
2016-12-06 21:18 ` Rob Herring
2016-12-01 23:43 ` [PATCH 16/22] drm: rcar-du: Add Gen3 HDMI encoder support Laurent Pinchart
2016-12-01 23:43 ` [PATCH 17/22] drm: rcar-du: Skip disabled outputs Laurent Pinchart
2016-12-01 23:43 ` [PATCH 18/22] drm: rcar-du: Add DPLL support Laurent Pinchart
2016-12-01 23:43 ` [PATCH 19/22] drm: rcar-du: Add HDMI outputs to R8A7795 device description Laurent Pinchart
2016-12-01 23:43 ` [PATCH 20/22] arm64: dts: r8a7795: Add HDMI encoder support Laurent Pinchart
2016-12-01 23:43 ` [PATCH 21/22] arm64: dts: r8a7795: salvator-x: Enable HDMI outputs Laurent Pinchart
2016-12-01 23:43 ` [PATCH 22/22] arm64: dts: r8a7795: salvator-x: Add DU1 and DU2 external dot clocks Laurent Pinchart
2016-12-02 11:11 ` [PATCH 00/22] R-Car Gen3 HDMI output support Jose Abreu
2016-12-02 11:11 ` Jose Abreu
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