From: Rob Herring <robh@kernel.org>
To: Vasily Khoruzhick <anarsoul@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org,
Archit Taneja <architt@codeaurora.org>,
Andrzej Hajda <a.hajda@samsung.com>,
David Airlie <airlied@linux.ie>,
linux-sunxi@googlegroups.com, dri-devel@lists.freedesktop.org,
Maxime Ripard <maxime.ripard@bootlin.com>,
Chen-Yu Tsai <wens@csie.org>,
Thierry Reding <thierry.reding@gmail.com>,
Sean Paul <seanpaul@chromium.org>,
Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
Daniel Vetter <daniel@ffwll.ch>,
linux-arm-kernel@lists.infradead.org,
Icenowy Zheng <icenowy@aosc.io>
Subject: Re: [PATCH v3 06/11] drm/sun4i: rgb: Add DT property to disable strict clock rate check
Date: Mon, 18 Feb 2019 12:26:29 -0600 [thread overview]
Message-ID: <20190218182629.GA14714@bogus> (raw)
In-Reply-To: <20190215050957.20755-7-anarsoul@gmail.com>
On Thu, Feb 14, 2019 at 09:09:52PM -0800, Vasily Khoruzhick wrote:
> Clock rate check that was added in commit bb43d40d7c83 ("drm/sun4i: rgb:
> Validate the clock rate") prevents some panel and bridges from working with
> sun4i driver.
Sounds lile a regression that should be reverted. The fix is not a
backwards compatible change either.
>
> Unfortunately, dotclock frequency for some modes are not achievable on
> sunxi hardware, and there's a slight deviation in rate returned by
> clk_round_rate(), so they fail this check.
>
> Experiments show that panels and bridges work fine with this slight
> deviation, e.g. Pinebook that uses ANX6345 bridge with 768p eDP panel
> requests 73 MHz, gets 72.296MHz instead (0.96% difference) and works just
> fine.
>
> This patch adds DT property to disable strict clock rate check
>
> Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
> ---
> .../devicetree/bindings/display/sunxi/sun4i-drm.txt | 2 ++
> drivers/gpu/drm/sun4i/sun4i_rgb.c | 5 +++++
> drivers/gpu/drm/sun4i/sun4i_tcon.c | 3 +++
> drivers/gpu/drm/sun4i/sun4i_tcon.h | 1 +
> 4 files changed, 11 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
> index f426bdb42f18..18c8b053a28d 100644
> --- a/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
> +++ b/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt
> @@ -63,6 +63,8 @@ Required properties:
> Documentation/devicetree/bindings/media/video-interfaces.txt. The
> first port should be the input endpoint. The second should be the
> output, usually to an HDMI connector.
> + - no-strict-clock-check: don't reject timings if exact dot clock can't be
> + reached.
This should be the default IMO. Most panels are a single timing, so if
we reject it the fallback no display?
I thought we had some mechanism already to allow some range of
frequencies. I think the chromeos guys needed something IIRC.
Rob
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next prev parent reply other threads:[~2019-02-18 18:26 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-15 5:09 [PATCH v3 00/11] Analogix ANX6345 RGB-(e)DP bridge support Vasily Khoruzhick
2019-02-15 5:09 ` [PATCH v3 01/11] drm/bridge: move ANA78xx driver to analogix subdirectory Vasily Khoruzhick
2019-02-15 5:09 ` [PATCH v3 02/11] drm/bridge: split some definitions of ANX78xx to dedicated headers Vasily Khoruzhick
2019-02-15 5:09 ` [PATCH v3 03/11] drm/bridge: extract some Analogix I2C DP common code Vasily Khoruzhick
2019-02-15 5:09 ` [PATCH v3 04/11] dt-bindings: Add ANX6345 DP/eDP transmitter binding Vasily Khoruzhick
2019-02-18 18:13 ` Rob Herring
2019-02-15 5:09 ` [PATCH v3 05/11] drm/bridge: Add Analogix anx6345 support Vasily Khoruzhick
2019-02-15 8:23 ` [linux-sunxi] " Priit Laes
2019-02-15 19:21 ` Vasily Khoruzhick
2019-02-15 9:13 ` Andrzej Hajda
2019-02-15 19:36 ` Vasily Khoruzhick
2019-02-26 7:12 ` Andrzej Hajda
2019-02-15 5:09 ` [PATCH v3 06/11] drm/sun4i: rgb: Add DT property to disable strict clock rate check Vasily Khoruzhick
2019-02-18 18:26 ` Rob Herring [this message]
2019-02-18 19:33 ` Vasily Khoruzhick
2019-02-19 8:56 ` Maxime Ripard
2019-02-19 15:44 ` Vasily Khoruzhick
2019-02-20 10:33 ` Maxime Ripard
2019-02-21 6:39 ` Vasily Khoruzhick
2019-02-21 6:41 ` Vasily Khoruzhick
2019-02-15 5:09 ` [PATCH v3 07/11] arm64: allwinner: a64: add pinmux for RGB666 LCD Vasily Khoruzhick
2019-02-15 5:09 ` [PATCH v3 08/11] drm/panel: simple: Add BOE HB140WX1-501 panel support Vasily Khoruzhick
2019-02-16 20:43 ` Sam Ravnborg
2019-02-16 20:48 ` Vasily Khoruzhick
2019-02-16 21:12 ` Sam Ravnborg
2019-02-15 5:09 ` [PATCH v3 09/11] dt-bindings: Add Guangdong Neweast Optoelectronics CO. LTD vendor prefix Vasily Khoruzhick
2019-02-18 18:27 ` Rob Herring
2019-02-15 5:09 ` [PATCH v3 10/11] drm/panel: simple: Add NewEast Optoelectronics CO., LTD WJFH116008A panel support Vasily Khoruzhick
2019-02-18 18:33 ` Rob Herring
2019-02-18 19:06 ` Vasily Khoruzhick
2019-02-19 14:54 ` Rob Herring
2019-02-19 21:35 ` Vasily Khoruzhick
2019-02-22 18:37 ` Rob Herring
2019-03-07 6:12 ` Vasily Khoruzhick
2019-02-15 5:09 ` [PATCH v3 11/11] arm64: allwinner: a64: enable LCD-related hardware for Pinebook Vasily Khoruzhick
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