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

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Date:   Wed, 23 Sep 2020 09:38:17 +0200
From:   Heiko Stübner <heiko@...ech.de>
To:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Jian-Hong Pan <jhp@...lessos.org>
Cc:     dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux@...lessm.com, Jian-Hong Pan <jhp@...lessos.org>
Subject: Re: [PATCH] drm/rockchip: skip probed failed device

Hi,

Am Mittwoch, 23. September 2020, 08:59:00 CEST schrieb Jian-Hong Pan:
> 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
> 
> 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;
> +			}

How does this relate to drivers doing EPROBE_DEFER?

Very often you have sub-drivers defering probe as they still need another
resource, so excluding them in that case would not work?

Heiko


>  
>  			device_link_add(dev, d, DL_FLAG_STATELESS);
>  			component_match_add(dev, &match, compare_dev, d);
>