AnsweredAssumed Answered

PTN3460I flickers and switches off display brightness

Question asked by Sergey Velykokhatko on Dec 31, 2019
Latest reply on Jan 17, 2020 by Tomas Vaverka

Hi all,

We are using PTN3460I and in new mainboard we got following effect in some boards: in several minutes after it switched on it starts to flicker and in several seconds display goes black. As I see the BLKTEN goes low. Since we are using Linux4.19 the activated KMS debugging shows that HPD generates IRQ and link training failed (s. messages bellow)

With oscilloscope I see realy two low pulses on HPD with nearly 0,7mS duration.

But could not find any reference in datasheet why the HPDRX pin of PTN3460I goes low during normal operation. Why it did so? Is it possible to get any further information from chip why it generated IRQ on HPD and what goes wrong in training phase?

 

Thanks an lot,

Happy new 2020

Sergey

 

[  115.092696] got hpd irq on port A - short
[  115.094502] DPDDC-A: 0x00000 AUX -> (ret= 15) 11 0a 82 01 00 03 01 81 00 01 00 00 0f 00 00
[  115.096919] DPCD: 11 0a 82 01 00 03 01 81 00 01 00 00 0f 00 00
[  115.098859] DPDDC-A: 0x00100 AUX <- (ret=  2) 0a 82
[  115.099727] DPDDC-A: 0x00200 AUX -> (ret=  1) 01
[  115.101554] DPDDC-A: 0x00107 AUX <- (ret=  2) 00 01
[  115.102245] DPDDC-A: 0x00080 AUX -> (ret= 16) 09 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  115.103222] Using vswing level 0
[  115.106305] Using pre-emphasis level 0
[  115.106840] DPDDC-A: 0x00201 AUX -> (ret=  1) 00
[  115.107441] Using DP training pattern TPS1
[  115.109184] DPDDC-A: 0x00202 AUX -> (ret=  6) 00 00 80 00 00 00
[  115.111512] DPDDC-A: 0x00102 AUX <- (ret=  3) 21 00 00
[  115.113559] DPDDC-A: 0x00202 AUX -> (ret=  6) 11 00 80 00 00 00
[  115.115252] clock recovery OK
[  115.116111] Using DP training pattern TPS2
[  115.117544] DPDDC-A: 0x00102 AUX <- (ret=  3) 22 00 00
[  115.119962] DPDDC-A: 0x00202 AUX -> (ret=  6) 71 00 80 00 11 00
[  115.121649] Using vswing level 1
[  115.122563] Using pre-emphasis level 0
[  115.123871] DPDDC-A: 0x00103 AUX <- (ret=  2) 01 01
[  115.126118] DPDDC-A: 0x00202 AUX -> (ret=  6) 71 00 80 00 22 00
[  115.127803] Using vswing level 2
[  115.128715] Using pre-emphasis level 0
[  115.130019] DPDDC-A: 0x00103 AUX <- (ret=  2) 02 02
[  115.132275] DPDDC-A: 0x00202 AUX -> (ret=  6) 71 00 80 00 33 00
[  115.133957] Using vswing level 3
[  115.134894] Using pre-emphasis level 0
[  115.136201] DPDDC-A: 0x00103 AUX <- (ret=  2) 27 27
[  115.138451] DPDDC-A: 0x00202 AUX -> (ret=  6) 71 00 00 00 33 00
[  115.140138] Using vswing level 3
[  115.141050] Using pre-emphasis level 0
[  115.142375] DPDDC-A: 0x00103 AUX <- (ret=  2) 27 27
[  115.144712] DPDDC-A: 0x00202 AUX -> (ret=  6) 71 00 00 00 33 00
[  115.146400] Using vswing level 3
[  115.147310] Using pre-emphasis level 0
[  115.148612] DPDDC-A: 0x00103 AUX <- (ret=  2) 27 27
[  115.149990] ln0_1:0x71 ln2_3:0x0 align:0x0 sink:0x0 adj_req0_1:0x33 adj_req2_3:0x0
[  115.149991] Channel equalization failed 5 times
[  115.153412] [CONNECTOR:81:eDP-1] Link Training failed at link rate = 270000, lane count = 2
[  115.153429] [CONNECTOR:81:eDP-1]
[  115.156729] DPDDC-A: 0x00102 AUX <- (ret=  1) 00
[  115.168003] DPDDC-A: 0x03000 AUX -> (ret=  1) 00
[  115.169720] DPDDC-A: 0x00201 AUX -> (ret=  1) 00
[  115.171540] DPDDC-A: 0x00202 AUX -> (ret=  6) 71 00 00 00 33 00
[  115.173269] running encoder hotplug functions
[  115.174818] Connector eDP-1 (pin 4) received hotplug event.
[  115.176476] [CONNECTOR:81:eDP-1]
[  115.178115] DPDDC-A: 0x00500 AUX -> (ret= 12) 00 60 37 33 34 36 30 49 00 11 01 00
[  115.180226] DP branch: OUI 00-60-37 dev-ID 3460I HW-rev 1.1 SW-rev 1.0 quirks 0x0000
[  115.183085] DPDDC-A: 0x00202 AUX -> (ret=  6) 71 00 00 00 33 00
[  115.185193] DPDDC-A: 0x03000 AUX -> (ret=  1) 00
[  115.186980] DPDDC-A: 0x00201 AUX -> (ret=  1) 00
[  115.188828] DPDDC-A: 0x00202 AUX -> (ret=  6) 71 00 00 00 33 00
[  118.199806] Turning eDP port A VDD off
[  118.200895] PP_STATUS: 0x80000008 PP_CONTROL: 0x00000067
[  118.202826] disabling DC off
[  118.203796] Enabling DC5
[  118.204515] Setting DC state from 00 to 01

Outcomes