Hi Laurent,
Am Dienstag, 6. Juni 2023, 17:12:29 CEST schrieb Laurent Pinchart:
> Hi Alexander,
>
> Thank you for the patch.
>
> On Tue, Jun 06, 2023 at 04:48:33PM +0200, Alexander Stein wrote:
> > When -EPROBE_DEFER is returned do not raise an error, but silently return
> > this error instead. Fixes error like this:
> > [drm:drm_bridge_attach] *ERROR* failed to attach bridge
> > /soc@0/bus@30800000/mipi-dsi@30a00000 to encoder None-34: -517
> > [drm:drm_bridge_attach] *ERROR* failed to attach bridge
> > /soc@0/bus@30800000/mipi-dsi@30a00000 to encoder None-34: -517
> >
> > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
> > ---
> > dev_err_probe() would be the best, but I am not sure if this function is
> > always used within a driver's probe() call.
> >
> > drivers/gpu/drm/drm_bridge.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
> > index c3d69af02e79d..07773d6441a1f 100644
> > --- a/drivers/gpu/drm/drm_bridge.c
> > +++ b/drivers/gpu/drm/drm_bridge.c
> > @@ -350,6 +350,7 @@ int drm_bridge_attach(struct drm_encoder *encoder,
> > struct drm_bridge *bridge,>
> > bridge->encoder = NULL;
> > list_del(&bridge->chain_node);
> >
> > + if (ret != -EPROBE_DEFER) {
> >
> > #ifdef CONFIG_OF
> >
> > DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n",
> >
> > bridge->of_node, encoder->name, ret);
>
> Wrong indentation.
Ah, right. Thanks for pointing out.
> dev_err_probe() could be useful, but this function is likely not called
> from probe paths only :-S
I was afraid this might be the cause. But I'm wondering in which situation
this can be the case, hence -EPROBE_DEFER could be returned then.
> When not called from a probe path, dropping the message will result in a
> silent error, which would be hard to debug :-(
On the other hand -EPROBE_DEFER is invalid on non-probe path also.
Assuming dev_err_probe is used here, an error will still be raised, -
EPROBE_DEFER should not occur then.
Best regards,
Alexander
> > @@ -357,6 +358,7 @@ int drm_bridge_attach(struct drm_encoder *encoder,
> > struct drm_bridge *bridge,>
> > DRM_ERROR("failed to attach bridge to encoder %s: %d\n",
> >
> > encoder->name, ret);
> >
> > #endif
> >
> > + }
> >
> > return ret;
> >
> > }
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