On Fri, Jul 10, 2015 at 10:43:11AM +0000, Wang J.W. wrote: > Hi Daniel, > > Thank you very much for your review! > See below... > > > -----Original Message----- > > From: Daniel Vetter [mailto:daniel.vetter@xxxxxxxx] On Behalf Of Daniel > > Vetter > > Sent: Friday, July 10, 2015 4:00 PM > > To: Wang Jianwei-B52261 > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux- > > arm-kernel@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; > > airlied@xxxxxxxx; daniel.vetter@xxxxxxxx; mark.yao@xxxxxxxxxxxxxx; Wood > > Scott-B07421; Wang Huan-B18965; Xiubo Li > > Subject: Re: [PATCH v6 1/4] drm/layerscape: Add Freescale DCU DRM driver > > > > On Fri, Jul 10, 2015 at 03:26:52PM +0800, Jianwei Wang wrote: > > > + .atomic_check = fsl_dcu_drm_encoder_atomic_check, > > > > .atomic_check is optional > > > > I try to remove .atomic_check, but it will cause CPU hang when starting up > And I find this in drivers/gpu/drm/drm_atomic_helper.c > > 293 if (funcs->atomic_check) { > 294 ret = funcs->atomic_check(encoder, crtc_state, > 295 conn_state); > 296 if (ret) { > 297 DRM_DEBUG_ATOMIC("[ENCODER:%d:%s] check failed\n", > 298 encoder->base.id, encoder->name); > 299 return ret; > 300 } > 301 } else { > 302 ret = funcs->mode_fixup(encoder, &crtc_state->mode, > 303 &crtc_state->adjusted_mode); > 304 if (!ret) { > 305 DRM_DEBUG_ATOMIC("[ENCODER:%d:%s] fixup failed\n", > 306 encoder->base.id, encoder->name); > 307 return -EINVAL; > 308 } > 309 } > It means that I have to implement at least one of atomic_check and mode_fixup. > So I reserve atomic_check. > Is there problem? Please give me some more comments if necessary. Thanks! Ah sorry you are right, atomic check is not optional. Unfortunately the optional-or-not thing has grown a bit organically so there's no clear rules. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
