Re: [PATCH 1/3] drm/msm: don't clean up priv->kms prematurely

[Abhinav Kumar]

On 4/21/2024 3:35 PM, Dmitry Baryshkov wrote:
> On Sat, Apr 20, 2024 at 04:02:00PM -0700, Abhinav Kumar wrote:
> > On 4/19/2024 7:33 PM, Dmitry Baryshkov wrote:
> > > MSM display drivers provide kms structure allocated during probe().
> > > Don't clean up priv->kms field in case of an error. Otherwise probe
> > > functions might fail after KMS probe deferral.
> >
> > So just to understand this more, this will happen when master component
> > probe (dpu) succeeded but other sub-component probe (dsi) deferred?
> >
> > Because if master component probe itself deferred it will allocate priv->kms
> > again isnt it and we will not even hit here.
>
> Master probing succeeds (so priv->kms is set), then kms_init fails at
> runtime, during binding of the master device. This results in probe
> deferral from the last component's component_add() function and reprobe
> attempt when possible (once the next device is added or probed). However
> as priv->kms is NULL, probe crashes.
>
> > > Fixes: a2ab5d5bb6b1 ("drm/msm: allow passing struct msm_kms to msm_drv_probe()")

Actually, Is this Fixes tag correct?

OR is this one better

Fixes: 506efcba3129 ("drm/msm: carve out KMS code from msm_drv.c")


> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > > ---
> > >    drivers/gpu/drm/msm/msm_kms.c | 1 -
> > >    1 file changed, 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/msm/msm_kms.c b/drivers/gpu/drm/msm/msm_kms.c
> > > index af6a6fcb1173..6749f0fbca96 100644
> > > --- a/drivers/gpu/drm/msm/msm_kms.c
> > > +++ b/drivers/gpu/drm/msm/msm_kms.c
> > > @@ -244,7 +244,6 @@ int msm_drm_kms_init(struct device *dev, const struct drm_driver *drv)
> > >    	ret = priv->kms_init(ddev);
> > >    	if (ret) {
> > >    		DRM_DEV_ERROR(dev, "failed to load kms\n");
> > > -		priv->kms = NULL;
> > >    		return ret;
> > >    	}