drm/i915: Fix assert_plane() warning on bootup with external display

On KBL, WHL RVPs, booting up with an external display connected, triggers
below warning, when the BiOS brings up the external display too.
This warning is not seen during hotplug.

[    3.615226] ------------[ cut here ]------------
[    3.619829] plane 1A assertion failure (expected on, current off)
[    3.632039] WARNING: CPU: 2 PID: 354 at drivers/gpu/drm/i915/intel_display.c:1294 assert_plane+0x71/0xbb
[    3.633920] iwlwifi 0000:00:14.3: loaded firmware version 38.c0e03d94.0 op_mode iwlmvm
[    3.647157] Modules linked in: iwlwifi cfg80211 btusb btrtl btbcm btintel bluetooth ecdh_generic
[    3.647163] CPU: 2 PID: 354 Comm: frecon Not tainted 4.17.0-rc7-50176-g655af12d39c2 #3
[    3.647165] Hardware name: Intel Corporation CoffeeLake Client Platform/WhiskeyLake U DDR4 ERB, BIOS CNLSFWR1.R00.X140.B00.1804040304 04/04/2018
[    3.684509] RIP: 0010:assert_plane+0x71/0xbb
[    3.764451] Call Trace:
[    3.766888]  intel_atomic_commit_tail+0xa97/0xb77
[    3.771569]  intel_atomic_commit+0x26a/0x279
[    3.771572]  drm_atomic_helper_set_config+0x5c/0x76
[    3.780670]  __drm_mode_set_config_internal+0x66/0x109
[    3.780672]  drm_mode_setcrtc+0x4c9/0x5cc
[    3.780674]  ? drm_mode_getcrtc+0x162/0x162
[    3.789774]  ? drm_mode_getcrtc+0x162/0x162
[    3.798108]  drm_ioctl_kernel+0x8d/0xe4
[    3.801926]  drm_ioctl+0x27d/0x368
[    3.805311]  ? drm_mode_getcrtc+0x162/0x162
[    3.805314]  ? selinux_file_ioctl+0x14e/0x199
[    3.805317]  vfs_ioctl+0x21/0x2f
[    3.813812]  do_vfs_ioctl+0x491/0x4b4
[    3.813813]  ? security_file_ioctl+0x37/0x4b
[    3.813816]  ksys_ioctl+0x55/0x75
[    3.820672]  __x64_sys_ioctl+0x1a/0x1e
[    3.820674]  do_syscall_64+0x51/0x5f
[    3.820678]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[    3.828221] RIP: 0033:0x7b5e04953967
[    3.835504] RSP: 002b:00007fff2eafb6f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[    3.835505] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007b5e04953967
[    3.835505] RDX: 00007fff2eafb730 RSI: 00000000c06864a2 RDI: 000000000000000f
[    3.835506] RBP: 00007fff2eafb720 R08: 0000000000000000 R09: 0000000000000000
[    3.835507] R10: 0000000000000070 R11: 0000000000000246 R12: 000000000000000f
[    3.879988] R13: 000056bc9dd7d210 R14: 00007fff2eafb730 R15: 00000000c06864a2
[    3.887081] Code: 48 c7 c7 06 71 a5 be 84 c0 48 c7 c2 06 fd a3 be 48 89 f9 48 0f 44 ca 84 db 48 0f 45 d7 48 c7 c7 df d3 a4 be 31 c0 e8 af a0 c0 ff <0f> 0b eb 2b 48 c7 c7 06 fd a3 be 84 c0 48 c7 c2 06 71 a5 be 48
[    3.905845] WARNING: CPU: 2 PID: 354 at drivers/gpu/drm/i915/intel_display.c:1294 assert_plane+0x71/0xbb
[    3.920964] ---[ end trace dac692f4ac46391a ]---

The warning is seen when mode_setcrtc() is called for pipeB
during bootup and before we get a mode_setcrtc() for pipeA,
while doing update_crtcs() in intel_atomic_commit_tail().
Now since, plane1A is still active after commit, update_crtcs()
is done for pipeA and eventually update_plane() for plane1A.

intel_plane_state->ctl for plane1A is not updated since set_modecrtc() is
called for pipeB. So intel_plane_state->ctl for plane 1A will be 0x0.
So doing an update_plane() for plane1A, will result in clearing
PLANE_CTL_ENABLE bit, and hence the warning.

To fix this warning, force all active planes to recompute their states
in probe.

Changes in v8:
- Actually add Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Changes in v7:
- Move call to intel_initial_commit() after sanitize_watermarks()
  Otherwise the plane update will still consult potentially bogus
  watermarks we read out from the hardware. (Ville)
- Carry Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
  from v6

Changes in v6:
- Handle EDEADLK for drm_atomic_get_crtc_state() and
  drm_atomic_add_affected_planes()
- Remove optimization of calling intel_initial_commit()
  only when there is more than one active pipe in probe.
- Avoid using intel_ types.

Changes in v5:
- Drop drm_modeset_lock_all_ctx() since locks will be taken later.

Changes in v4:
- Handle locking in intel_initial_commit()
- Move the for loop inside intel_initial_commit() so that
  drm_atomic_commit() is called only once
- Call intel_initial_commit() only for more than one active crtc on boot.
- Save the return value of intel_initial_commit() and print a message in
  case of an error

Changes in v3:
- Add comments

Changes in v2:
- Force all planes to recompute their states.(Ville Syrjälä)
- Update the commit message

Signed-off-by: Azhar Shaikh <azhar.shaikh@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1530902250-44583-1-git-send-email-azhar.shaikh@intel.com