Hi Stephen, On Wed, Nov 16, 2022 at 10:57:02AM +1100, Stephen Rothwell wrote: > Hi all, > > Today's linux-next merge of the drm-misc tree got a conflict in: > > drivers/gpu/drm/vc4/vc4_hdmi.c > > between commit: > > 682f99b8ae88 ("drm/vc4: hdmi: Take our lock to reset the link") > > from the origin tree and commits: > > d218750805a3 ("drm/vc4: hdmi: Pass vc4_hdmi to vc4_hdmi_supports_scrambling()") > 0a99962c0dbf ("drm/vc4: hdmi: Fix pointer dereference before check") > > from the drm-misc tree. > > I fixed it up (see below) and can carry the fix as necessary. This > is now fixed as far as linux-next is concerned, but any non trivial > conflicts should be mentioned to your upstream maintainer when your tree > is submitted for merging. You may also want to consider cooperating > with the maintainer of the conflicting tree to minimise any particularly > complex conflicts. > > -- > Cheers, > Stephen Rothwell > > diff --cc drivers/gpu/drm/vc4/vc4_hdmi.c > index d7fcc7a4c082,6b223a5fcf6f..000000000000 > --- a/drivers/gpu/drm/vc4/vc4_hdmi.c > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c > @@@ -349,12 -348,9 +348,13 @@@ static int vc4_hdmi_reset_link(struct d > if (!crtc_state->active) > return 0; > > + mutex_lock(&vc4_hdmi->mutex); > + > - if (!vc4_hdmi_supports_scrambling(encoder)) { > + vc4_hdmi = connector_to_vc4_hdmi(connector); > - if (!vc4_hdmi_supports_scrambling(vc4_hdmi)) > ++ if (!vc4_hdmi_supports_scrambling(vc4_hdmi)) { > + mutex_unlock(&vc4_hdmi->mutex); > return 0; > + } > > scrambling_needed = vc4_hdmi_mode_needs_scrambling(&vc4_hdmi->saved_adjusted_mode, > vc4_hdmi->output_bpc, This resolution is not quite right, as pointed out by clang: drivers/gpu/drm/vc4/vc4_hdmi.c:351:14: error: variable 'vc4_hdmi' is uninitialized when used here [-Werror,-Wuninitialized] mutex_lock(&vc4_hdmi->mutex); ^~~~~~~~ ./include/linux/mutex.h:187:44: note: expanded from macro 'mutex_lock' #define mutex_lock(lock) mutex_lock_nested(lock, 0) ^~~~ drivers/gpu/drm/vc4/vc4_hdmi.c:322:27: note: initialize the variable 'vc4_hdmi' to silence this warning struct vc4_hdmi *vc4_hdmi; ^ = NULL 1 error generated. Obviously, the assignment of vc4_hdmi should be before mutex_lock(). Cheers, Nathan