Dave -
My Haswell oopses when power cycling an MST enabled Dell P2415Q display.
I haven't been able to get a picture on screen when either the sink or the source has MST enabled, but one thing at a time...
Below is the only snippet of dmesg I've been able to squeeze out at this time, maybe it gives you some clues. I just crudely tail -f /proc/kmsg to get something out so it's less than perfect.
I've been eyeballing drm_dp_add_port with suspicion. It looks like if port == NULL (and thus created is true) *and* port_msg->port_number >= 8, drm_get_edid gets called with an uninitialized port->aux.ddc. My quick attempts at changing the conditions for calling drm_dp_port_teardown_pdt and drm_dp_port_setup_pdt were, however, unsuccesful.
Any ideas?
In the mean time I'll try to scavenge another MST source so I don't have to keep rebooting my main dev machine... ;)
BR, Jani.
<7>[ 987.227610] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:48:HDMI-A-2] disconnected <7>[ 987.227613] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:48:HDMI-A-2] <7>[ 987.227770] [drm:gmbus_xfer] GMBUS [i915 gmbus dpc] NAK for addr: 0050 r(1) <7>[ 987.227772] [drm:drm_helper_probe_single_connector_modes_merge_bits] [CONNECTOR:48:HDMI-A-2] disconnected <7>[ 993.630496] [drm:intel_dp_print_rates] sink rates: 162000, 270000, 540000 <7>[ 993.631248] [drm:intel_dp_probe_oui] Sink OUI: 000000 <7>[ 993.631852] [drm:intel_dp_probe_mst] Sink is MST capable <7>[ 993.656698] [drm:intel_hpd_irq_handler] hotplug event received, stat 0x00200000, dig 0x00101011 <7>[ 993.656702] [drm:intel_hpd_irq_handler] digital hpd port B - short <7>[ 993.656719] [drm:intel_dp_hpd_pulse] got hpd irq on port B - short <7>[ 993.662942] [drm:intel_dp_check_mst_status] got esi 41 10 00 <7>[ 993.664008] [drm:intel_dp_check_mst_status] got esi2 41 00 00 <7>[ 993.664010] [drm:intel_dp_check_mst_status] got esi 41 00 00 <7>[ 993.668159] [drm:intel_hpd_irq_handler] digital hpd port B - short <7>[ 993.668597] [drm:intel_dp_check_mst_status] got esi 41 10 00 <7>[ 993.669095] [drm:drm_dp_send_link_address] port 0: input 1, pdt: 1, pn: 0, dpcd_rev: 00, mcs: 1, ddps: 1, ldps 0, sdp 0/0 <7>[ 993.669100] [drm:drm_dp_send_link_address] port 2: input 0, pdt: 0, pn: 8, dpcd_rev: 00, mcs: 0, ddps: 0, ldps 0, sdp 0/0 <1>[ 993.669333] IP: [<ffffffffa03c2c30>] i2c_transfer+0x10/0xd0 [i2c_core] <4>[ 993.669378] Oops: 0000 [#1] SMP af_alg hid_generic usbhid hid dm_crypt dm_mod sg sd_mod rtsx_pci_sdmmc mmc_core crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd ahci libahci libata scsi_mod xhci_pci ehci_pci e1000e rtsx_pci xhci_hcd ehci_hcd mfd_core ptp pps_core usbcore usb_common thermal thermal_sys <4>[ 993.670009] Hardware name: Notebook W740SU /W740SU , BIOS 4.6.5 04/21/2014 <4>[ 993.670100] task: ffff880409bb0be0 ti: ffff880409bb8000 task.ti: ffff880409bb8000 <4>[ 993.670173] RSP: 0018:ffff880409bbbb18 EFLAGS: 00010246 <4>[ 993.670226] RDX: 0000000000000002 RSI: ffff880409bbbb68 RDI: ffff880409ec7840 <4>[ 993.670287] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000002 <4>[ 993.670348] FS: 0000000000000000(0000) GS:ffff88041f600000(0000) knlGS:0000000000000000 <4>[ 993.670406] CR2: 0000000000000000 CR3: 000000000180d000 CR4: 00000000001407f0 <4>[ 993.670446] 0000000000000005 0000000000000001 0000000000000002 ffffffffa046045c <4>[ 993.670518] 0000000100000030 ffff880409bbbb57 ffff000100000050 ffff880409bbbb56 <4>[ 993.670574] [<ffffffffa046045c>] ? drm_do_probe_ddc_edid+0xcc/0x150 [drm] <4>[ 993.670647] [<ffffffffa05f58a5>] ? intel_dp_add_mst_connector+0x115/0x140 [i915] <4>[ 993.670716] [<ffffffff815642d2>] ? printk+0x4d/0x52 <4>[ 993.670774] [<ffffffffa04f18db>] ? drm_dp_send_link_address+0x17b/0x220 [drm_kms_helper] <4>[ 993.670850] [<ffffffff81087cbd>] ? process_one_work+0x14d/0x410 <4>[ 993.670902] [<ffffffff815668b0>] ? __schedule+0x2a0/0x8f0 <4>[ 993.670953] [<ffffffff8108d993>] ? kthread+0xd3/0xf0 <4>[ 993.671004] [<ffffffff8156b162>] ? ret_from_fork+0x42/0x70 <4>[ 993.671057] Code: ff ff 45 31 ed e9 c4 fe ff ff 45 31 e4 e9 55 fd ff ff 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 54 55 53 48 8b 47 10 48 89 fb <48> 83 38 00 0f 84 86 00 00 00 65 8b 05 9f 8d c4 5f a9 ff ff df <4>[ 993.671241] RSP <ffff880409bbbb18> <4>[ 993.684371] ---[ end trace 34f0c3d1ac8f2574 ]--- <1>[ 993.684455] BUG: unable to handle kernel paging request at ffffffffffffffd8 <1>[ 993.684492] IP: [<ffffffff8108dfac>] kthread_data+0xc/0x20 <4>[ 993.684525] PGD 1810067 PUD 1812067 PMD 0 <4>[ 993.684569] Modules linked in: uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_core v4l2_common videodev media binfmt_misc bnep nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc joydev nls_utf8 nls_cp437 vfat snd_hda_