linux-kernel - Re: [PATCH] drm/bridge: synopsys/dw-hdmi: set cec clock rate

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Date:   Wed, 26 Jan 2022 17:32:55 -0300
From:   Fabio Estevam <festevam@...il.com>
To:     Peter Geis <pgwipeout@...il.com>
Cc:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Robert Foss <robert.foss@...aro.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Pierre-Hugues Husson <phh@....me>,
        Archit Taneja <architt@...eaurora.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        DRI mailing list <dri-devel@...ts.freedesktop.org>,
        linux-rockchip@...ts.infradead.org,
        Robin Murphy <robin.murphy@....com>
Subject: Re: [PATCH] drm/bridge: synopsys/dw-hdmi: set cec clock rate

On Wed, Jan 26, 2022 at 5:25 PM Peter Geis <pgwipeout@...il.com> wrote:

> +
> +               ret = clk_set_rate(hdmi->cec_clk, HDMI_CEC_CLK_RATE);
> +               if (ret)
> +                       dev_warn(hdmi->dev, "Cannot set HDMI cec clock rate: %d\n", ret);

You are setting the cec clock rate after it has been enabled, which
can be glitchy.

Better to set the rate prior to enabling the clock.