linux-kernel - Re: [PATCH] drm/rockchip: skip probed failed device

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Message-ID: <439c4b59-b1e6-88bb-568e-1c2a0feceed4@arm.com>
Date:   Wed, 23 Sep 2020 12:05:26 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Jian-Hong Pan <jhp@...lessos.org>,
        Heiko Stübner <heiko@...ech.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        linux-rockchip@...ts.infradead.org, linux@...lessm.com,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] drm/rockchip: skip probed failed device

On 2020-09-23 07:59, Jian-Hong Pan wrote:
> The cdn-dp sub driver probes the device failed on PINEBOOK Pro.
> 
> kernel: cdn-dp fec00000.dp: [drm:cdn_dp_probe [rockchipdrm]] *ERROR* missing extcon or phy
> kernel: cdn-dp: probe of fec00000.dp failed with error -22

Wouldn't it make more sense to simply not enable the DisplayPort node in 
the upstream DT, until the type-C phy work has been done to make it 
usable at all? AIUI the "official" Manjaro kernel is carrying a bunch of 
hacks to make type-C work via extcon, but they know that isn't an 
upstreamable solution.

Robin.

> Then, the device halts all of the DRM related device jobs. For example,
> the operations: vop_component_ops, vop_component_ops and
> rockchip_dp_component_ops cannot be bound to corresponding devices. So,
> Xorg cannot find the correct DRM device.
> 
> This patch skips the probing failed devices to fix this issue.
> 
> Link: http://lists.infradead.org/pipermail/linux-rockchip/2020-September/022352.html
> Signed-off-by: Jian-Hong Pan <jhp@...lessos.org>
> ---
>   drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> index 0f3eb392fe39..de13588602b4 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
> @@ -331,6 +331,12 @@ static struct component_match *rockchip_drm_match_add(struct device *dev)
>   
>   			if (!d)
>   				break;
> +			if (!d->driver) {
> +				DRM_DEV_ERROR(d,
> +					      "%s did not probe successfully",
> +					      drv->driver.name);
> +				continue;
> +			}
>   
>   			device_link_add(dev, d, DL_FLAG_STATELESS);
>   			component_match_add(dev, &match, compare_dev, d);
>