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From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Alejandro Hernandez <ajhernandez@ti.com>,
	Jyri Sarha <jsarha@ti.com>,
	dri-devel@lists.freedesktop.org
Subject: Re: [PATCH 2/7] drm/omap: tweak HDMI DDC timings
Date: Tue, 3 Sep 2019 17:23:53 +0300	[thread overview]
Message-ID: <20190903142353.GE4812@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20190902125359.18001-3-tomi.valkeinen@ti.com>

Hi Tomi,

Thank you for the path.

On Mon, Sep 02, 2019 at 03:53:54PM +0300, Tomi Valkeinen wrote:
> From: Alejandro Hernandez <ajhernandez@ti.com>
> 
> A "HDMI I2C Master Error" is sometimes reported with the current DDC SCL
> timings. The current settings for a 10us SCL period (100 KHz) causes the
> error with some displays.  This patch increases the SCL signal period
> from 10us to 10.2us, with the new settings the error is not observed
> 

It would be useful to document what those "some displays" are if you
can.

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> Signed-off-by: Alejandro Hernandez <ajhernandez@ti.com>
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> ---
>  drivers/gpu/drm/omapdrm/dss/hdmi5_core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/omapdrm/dss/hdmi5_core.c b/drivers/gpu/drm/omapdrm/dss/hdmi5_core.c
> index 7400fb99d453..4c588ec7634a 100644
> --- a/drivers/gpu/drm/omapdrm/dss/hdmi5_core.c
> +++ b/drivers/gpu/drm/omapdrm/dss/hdmi5_core.c
> @@ -39,8 +39,8 @@ static void hdmi_core_ddc_init(struct hdmi_core_data *core)
>  {
>  	void __iomem *base = core->base;
>  	const unsigned long long iclk = 266000000;	/* DSS L3 ICLK */
> -	const unsigned int ss_scl_high = 4600;		/* ns */
> -	const unsigned int ss_scl_low = 5400;		/* ns */
> +	const unsigned int ss_scl_high = 4700;		/* ns */
> +	const unsigned int ss_scl_low = 5500;		/* ns */
>  	const unsigned int fs_scl_high = 600;		/* ns */
>  	const unsigned int fs_scl_low = 1300;		/* ns */
>  	const unsigned int sda_hold = 1000;		/* ns */

-- 
Regards,

Laurent Pinchart
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  reply	other threads:[~2019-09-03 14:24 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-02 12:53 [PATCH 0/7] drm/omap: misc improvements Tomi Valkeinen
2019-09-02 12:53 ` [PATCH 1/7] drm/omap: drop unneeded locking from mgr_fld_write() Tomi Valkeinen
2019-09-03 14:14   ` Laurent Pinchart
2019-09-02 12:53 ` [PATCH 2/7] drm/omap: tweak HDMI DDC timings Tomi Valkeinen
2019-09-03 14:23   ` Laurent Pinchart [this message]
2019-09-26 12:54     ` Tomi Valkeinen
2019-09-26 14:40       ` Alejandro Hernandez
2019-09-02 12:53 ` [PATCH 3/7] drm/omap: fix missing scaler pixel fmt limitations Tomi Valkeinen
2019-09-03 15:12   ` Laurent Pinchart
2019-09-26 12:55     ` Tomi Valkeinen
2019-09-02 12:53 ` [PATCH 4/7] drm/omap: Implement CTM property for CRTC using OVL managers CPR matrix Tomi Valkeinen
2019-09-03 15:24   ` Laurent Pinchart
     [not found]     ` <b44372e2-1bb7-ddb8-d121-ae096b38d918@ti.com>
2019-09-04 11:11       ` Laurent Pinchart
2019-09-04 20:08         ` Jyri Sarha
2019-09-04 20:20           ` Ilia Mirkin
2020-09-21 11:08             ` Tomi Valkeinen
2020-09-21 11:49               ` Pekka Paalanen
2020-09-22  7:44                 ` Tomi Valkeinen
2020-09-22  9:48                   ` Pekka Paalanen
2020-09-22 10:02                   ` Daniel Stone
2019-09-04 21:52           ` Laurent Pinchart
2019-09-05 10:00             ` Jyri Sarha
2019-09-05 10:05               ` Laurent Pinchart
2019-09-05 13:48                 ` Jyri Sarha
2019-09-02 12:53 ` [PATCH 5/7] drm/omap: Enable COLOR_ENCODING and COLOR_RANGE properties for planes Tomi Valkeinen
2019-09-03 15:32   ` Laurent Pinchart
2019-09-05  9:24     ` Jyri Sarha
2019-09-05  9:43       ` Laurent Pinchart
2019-09-02 12:53 ` [PATCH 6/7] drm/omap: dss: platform_register_drivers() to dss.c and remove core.c Tomi Valkeinen
2019-09-03 15:34   ` Laurent Pinchart
2019-09-04  6:47     ` Jyri Sarha
2019-09-02 12:53 ` [PATCH 7/7] drm/omap: hdmi5: automatically choose limited/full range output Tomi Valkeinen
2019-09-03 15:38   ` Laurent Pinchart

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