linux-kernel - Re: [PATCH v4 3/3] drm/bridge: ti-sn65dsi86: Support hotplug detection

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Date:   Wed, 23 Mar 2022 14:47:17 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Kieran Bingham <kieran.bingham+renesas@...asonboard.com>
Cc:     Sam Ravnborg <sam@...nborg.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Robert Foss <robert.foss@...aro.org>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 3/3] drm/bridge: ti-sn65dsi86: Support hotplug detection

Hi,

On Thu, Mar 17, 2022 at 6:13 AM Kieran Bingham
<kieran.bingham+renesas@...asonboard.com> wrote:
>
> @@ -1241,9 +1350,32 @@ static int ti_sn_bridge_probe(struct auxiliary_device *adev,
>         pdata->bridge.type = pdata->next_bridge->type == DRM_MODE_CONNECTOR_DisplayPort
>                            ? DRM_MODE_CONNECTOR_DisplayPort : DRM_MODE_CONNECTOR_eDP;
>
> -       if (pdata->bridge.type == DRM_MODE_CONNECTOR_DisplayPort)
> +       if (pdata->bridge.type == DRM_MODE_CONNECTOR_DisplayPort) {
>                 pdata->bridge.ops = DRM_BRIDGE_OP_EDID;
>
> +               if (!pdata->no_hpd)
> +                       pdata->bridge.ops |= DRM_BRIDGE_OP_DETECT;
> +       }
> +
> +       if (!pdata->no_hpd && pdata->irq > 0) {
> +               ret = devm_request_threaded_irq(pdata->dev, pdata->irq, NULL,
> +                                               ti_sn65dsi86_irq_handler,
> +                                               IRQF_ONESHOT, "sn65dsi86-irq",
> +                                               pdata);
> +               if (ret)
> +                       return dev_err_probe(pdata->dev, ret,
> +                                            "Failed to register DP interrupt\n");
> +
> +               /* Enable IRQ based HPD */
> +               pdata->bridge.ops |= DRM_BRIDGE_OP_HPD;
> +
> +               /*
> +                * Keep the IRQ disabled initially. It will only be enabled when
> +                * requested through ti_sn_bridge_hpd_enable().
> +                */
> +               disable_irq(pdata->irq);

Instead, I think you should use `IRQF_NO_AUTOEN` which makes sure that
no matter what the state of the hardware is your IRQ won't fire
"early". ...and, of course, it saves a line of code. ;-)

Other than that this looks nice to me now so feel free to add my
Reviewed-by tag after the above is fixed.

-Doug