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

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Message-ID: <CAPpJ_efjVXq6BNQDfiwmEYPyjJyBH5xP2hBdGdNjT7E7=fkMXw@mail.gmail.com>
Date:   Thu, 24 Sep 2020 14:07:04 +0800
From:   Jian-Hong Pan <jhp@...lessos.org>
To:     Heiko Stübner <heiko@...ech.de>
Cc:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Robin Murphy <robin.murphy@....com>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        linux-rockchip@...ts.infradead.org,
        Linux Upstreaming Team <linux@...lessm.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] drm/rockchip: skip probed failed device

Heiko Stübner <heiko@...ech.de> 於 2020年9月23日 週三 下午7:16寫道：
>
> Am Mittwoch, 23. September 2020, 13:05:26 CEST schrieb Robin Murphy:
> > 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?
>
> Or alternatively just disable the cdn-dp Rockchip driver in the kernel config,
> which results in it also not getting probed.

This may be the simplest way.
However, considering generic distro kernels have a policy to enable
all drivers, disabling the DisplayPort node in the upstream DT, until
the type-C phy work has been done may be a better solution for now.
I can prepare a patch for this.

Jian-Hong Pan

> > 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);