[Intel-gfx] assertion on intel_disable_transcoder

[Wang, Xingchao]

Hi Daniel/Paulo,

It's easy to see such WARNING in dmesg, the DDI port is not disabled prior to disable transcoder.
I am not sure it will impact the Pipe/transcoder/DDI-port configurations, anyway after some times WARNING, I could not make HDMI audio work anymore.
With intel_audio_dump I could see the related configurations was totally disabled.

DDI_BUF_CTL_A         0x00000080  DDI Buffer Controler A
DDI_BUF_CTL_B         0x00000000  DDI Buffer Controler B
DDI_BUF_CTL_C         0x00000080  DDI Buffer Controler C
DDI_BUF_CTL_D         0x00000000  DDI Buffer Controler D
DDI_BUF_CTL_E         0x80000002  DDI Buffer Controler E
PIPE_CONF_A           0x00000000  PIPE Configuration A
PIPE_CONF_B           0x00000000  PIPE Configuration B
PIPE_CONF_C           0x00000000  PIPE Configuration C
PIPE_CONF_EDP         0x00000000  PIPE Configuration EDP
PIPE_DDI_FUNC_CTL_A   0xc4034002  PIPE DDI Function Control A
PIPE_DDI_FUNC_CTL_B   0xa0035000  PIPE DDI Function Control B
PIPE_DDI_FUNC_CTL_C   0x00030000  PIPE DDI Function Control C
PIPE_DDI_FUNC_CTL_EDP 0x00030000  PIPE DDI Function Control EDP
TRANS_CONF            0x00000000  Transcoder Configuration

Thanks
--xingchao

[   16.835658] ------------[ cut here ]------------
[   16.835690] WARNING: at drivers/gpu/drm/i915/intel_display.c:1118 assert_fdi_tx+0x87/0x90 [i915]()
[   16.835691] Hardware name: Shark Bay Client platform
[   16.835692] FDI TX state assertion failure (expected off, current on)
[   16.835706] Modules linked in: snd_seq_midi_event i915(+) snd_seq snd_timer drm_kms_helper snd_seq
_device ghash_clmulni_intel drm aesni_intel snd cryptd mcs7830 usbnet joydev aes_x86_64 soundcore psm
ouse snd_page_alloc hid_generic i2c_algo_bit serio_raw video mac_hid microcode lpc_ich lp parport e10
00e usbhid hid
[   16.835708] Pid: 470, comm: modprobe Not tainted 3.5.0-rc46patches+ #12
[   16.835709] Call Trace:
[   16.835715]  [<ffffffff8105278f>] warn_slowpath_common+0x7f/0xc0
[   16.835718]  [<ffffffff81052886>] warn_slowpath_fmt+0x46/0x50
[   16.835728]  [<ffffffffa01cc847>] assert_fdi_tx+0x87/0x90 [i915]
[   16.835739]  [<ffffffffa01d5cf5>] ironlake_crtc_disable+0x185/0x820 [i915]
[   16.835748]  [<ffffffffa01d641e>] ironlake_crtc_dpms+0x8e/0xa0 [i915]
[   16.835756]  [<ffffffffa01cdbd8>] intel_crtc_dpms+0x48/0x140 [i915]
[   16.835768]  [<ffffffffa01d49d5>] intel_crtc_disable+0x35/0xb0 [i915]
[   16.835772]  [<ffffffffa012d6a5>] drm_helper_disable_unused_functions+0x115/0x190 [drm_kms_helper]
[   16.835785]  [<ffffffffa01d849d>] intel_modeset_init+0x8ad/0xf90 [i915]
[   16.835796]  [<ffffffffa01aebba>] i915_driver_load+0xa8a/0xb90 [i915]
[   16.835812]  [<ffffffffa016fa7b>] ? drm_get_minor+0x26b/0x310 [drm]
[   16.835819]  [<ffffffffa0171e71>] drm_get_pci_dev+0x191/0x2b0 [drm]
[   16.835834]  [<ffffffffa01fc01b>] i915_pci_probe+0x4f/0x57 [i915]
[   16.835837]  [<ffffffff8134230c>] local_pci_probe+0x5c/0xd0
[   16.835840]  [<ffffffff81343c49>] pci_device_probe+0x109/0x130
[   16.835843]  [<ffffffff814065ee>] driver_probe_device+0x7e/0x220
[   16.835845]  [<ffffffff8140683b>] __driver_attach+0xab/0xb0
[   16.835848]  [<ffffffff81406790>] ? driver_probe_device+0x220/0x220
[   16.835850]  [<ffffffff81404a26>] bus_for_each_dev+0x56/0x90
[   16.835852]  [<ffffffff8140610e>] driver_attach+0x1e/0x20
[   16.835854]  [<ffffffff81405cc0>] bus_add_driver+0x1a0/0x270
[   16.835856]  [<ffffffff81406d96>] driver_register+0x76/0x130
[   16.835859]  [<ffffffff81343916>] __pci_register_driver+0x56/0xd0
[   16.835862]  [<ffffffff8166949d>] ? notifier_call_chain+0x4d/0x70
[   16.835869]  [<ffffffffa01720aa>] drm_pci_init+0x11a/0x130 [drm]
[   16.835871]  [<ffffffffa0230000>] ? 0xffffffffa022ffff
[   16.835880]  [<ffffffffa0230066>] i915_init+0x66/0x68 [i915]
[   16.835884]  [<ffffffff8100203f>] do_one_initcall+0x3f/0x170
[   16.835887]  [<ffffffff810b581e>] sys_init_module+0xbe/0x230
[   16.835890]  [<ffffffff8166d769>] system_call_fastpath+0x16/0x1b
[   16.835891] ---[ end trace bd9532eaee4e4542 ]---