drm/msm/dpu: Delete bonkers code

dpu_crtc_atomic_flush() was directly poking it's attached planes in a
code path that ended up in dpu_plane_atomic_update(), even if the plane
was not involved in the current atomic update. While a bit dubious,
this worked before because plane->state would always point to something
valid. But now using drm_atomic_get_new_plane_state() we could get a
NULL state pointer instead, leading to:

[ 20.873273] Call trace:
[ 20.875740] dpu_plane_atomic_update+0x5c/0xed0
[ 20.880311] dpu_plane_restore+0x40/0x88
[ 20.884266] dpu_crtc_atomic_flush+0xf4/0x208
[ 20.888660] drm_atomic_helper_commit_planes+0x150/0x238
[ 20.894014] msm_atomic_commit_tail+0x1d4/0x7a0
[ 20.898579] commit_tail+0xa4/0x168
[ 20.902102] drm_atomic_helper_commit+0x164/0x178
[ 20.906841] drm_atomic_commit+0x54/0x60
[ 20.910798] drm_atomic_connector_commit_dpms+0x10c/0x118
[ 20.916236] drm_mode_obj_set_property_ioctl+0x1e4/0x440
[ 20.921588] drm_connector_property_set_ioctl+0x60/0x88
[ 20.926852] drm_ioctl_kernel+0xd0/0x120
[ 20.930807] drm_ioctl+0x21c/0x478
[ 20.934235] __arm64_sys_ioctl+0xa8/0xe0
[ 20.938193] invoke_syscall+0x64/0x130
[ 20.941977] el0_svc_common.constprop.3+0x5c/0xe0
[ 20.946716] do_el0_svc+0x80/0xa0
[ 20.950058] el0_svc+0x20/0x30
[ 20.953145] el0_sync_handler+0x88/0xb0
[ 20.957014] el0_sync+0x13c/0x140

The reason for the codepath seems dubious, the atomic suspend/resume
heplers should handle the power-collapse case. If not, the CRTC's
atomic_check() should be adding the planes to the atomic update.

Reported-by: Stephen Boyd <[e-mail]>
Reported-by: John Stultz <[e-mail]>
Fixes: 37418bf14c13 ("drm: Use state helper instead of the plane state pointer")
Tested-by: John Stultz <[e-mail]>
Signed-off-by: Rob Clark <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c

···
 	if (unlikely(!cstate->num_mixers))
 		return;
 
-	/*
-	 * For planes without commit update, drm framework will not add
-	 * those planes to current state since hardware update is not
-	 * required. However, if those planes were power collapsed since
-	 * last commit cycle, driver has to restore the hardware state
-	 * of those planes explicitly here prior to plane flush.
-	 */
-	drm_atomic_crtc_for_each_plane(plane, crtc)
-		dpu_plane_restore(plane, state);
-
 	/* update performance setting before crtc kickoff */
 	dpu_core_perf_crtc_update(crtc, 1, false);
 

drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c

···
 	}
 }
 
-void dpu_plane_restore(struct drm_plane *plane, struct drm_atomic_state *state)
-{
-	struct dpu_plane *pdpu;
-
-	if (!plane || !plane->state) {
-		DPU_ERROR("invalid plane\n");
-		return;
-	}
-
-	pdpu = to_dpu_plane(plane);
-
-	DPU_DEBUG_PLANE(pdpu, "\n");
-
-	dpu_plane_atomic_update(plane, state);
-}
-
 static void dpu_plane_destroy(struct drm_plane *plane)
 {
 	struct dpu_plane *pdpu = plane ? to_dpu_plane(plane) : NULL;

drivers/gpu/drm/msm/disp/dpu1/dpu_plane.h

···
 		u32 *flush_sspp);
 
 /**
- * dpu_plane_restore - restore hw state if previously power collapsed
- * @plane: Pointer to drm plane structure
- */
-void dpu_plane_restore(struct drm_plane *plane, struct drm_atomic_state *state);
-
-/**
  * dpu_plane_flush - final plane operations before commit flush
  * @plane: Pointer to drm plane structure
  */