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@ffwll.ch] On Behalf Of Daniel Vetter Sent: Friday, July 10, 2015 4:00 PM To: Wang Jianwei-B52261 Cc: dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org; linux- arm-kernel@lists.infradead.org; devicetree@vger.kernel.org; airlied@linux.ie; daniel.vetter@ffwll.ch; mark.yao@rock-chips.com; 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