Booting Hikey960 without display attached?

Products Support HiKey 960
#1

Hi,

After building latest AOSP master (Apr, 23rd “known good” manifest) and K4.14, I get Android successfully booted when an HDMI display is attached.

But… For some reason I need to boot the board without any display.
This was actually possible with earlier AOSP master (last Sep, 2018) and K4.9 without any tweak.

For example, the sys.boot_completed property is not set,
and getting such periodic error message when no display attached:

console:/ $ [ 390.397635] init: starting service ‘netd’…
[ 390.407552] init: Created socket ‘/dev/socket/netd’, mode 660, user 0, group 1000
[ 390.416555] init: Created socket ‘/dev/socket/dnsproxyd’, mode 660, user 0, group 3003
[ 390.425637] init: Created socket ‘/dev/socket/mdns’, mode 660, user 0, group 1000
[ 390.432286] init: starting service ‘zygote’…
[ 390.434047] init: Created socket ‘/dev/socket/fwmarkd’, mode 660, user 0, group 3003
[ 390.444460] init: Created socket ‘/dev/socket/zygote’, mode 660, user 0, group 1000
[ 390.452056] init: starting service ‘zygote_secondary’…
[ 390.453619] init: Created socket ‘/dev/socket/blastula_pool’, mode 660, user 0, group 1000
[ 390.462809] init: starting service ‘audioserver’…
[ 390.706846] logd: logdr: UID=1000 GID=1003 PID=8150 n tail=50 logMask=8 pid=8102 start=0ns timeout=0ns
[ 390.718821] logd: logdr: UID=1000 GID=1003 PID=8150 n tail=50 logMask=1 pid=8102 start=0ns timeout=0ns
[ 390.750836] logd: logdr: UID=1000 GID=1003 PID=8150 n tail=0 logMask=8 pid=8102 start=0ns timeout=0ns
[ 390.764385] logd: logdr: UID=1000 GID=1003 PID=8150 n tail=0 logMask=1 pid=8102 start=0ns timeout=0ns
[ 390.804684] binder: release 8102:8102 transaction 42122 in, still active
[ 390.811423] binder: release 8102:8102 transaction 42117 out, still active
[ 390.818366] binder: send failed reply for transaction 42122 to 2518:2646
[ 390.825341] binder: 2518:2646 transaction failed 29189/0, size 4-0 line 3050
[ 390.832443] binder: send failed reply for transaction 42117, target dead

Any hint with kernel build configuration, or command line is appreciated!

Thanks & Regards.

#2

or maybe is this bug related ?
https://bugs.96boards.org/show_bug.cgi?id=830

#3

Hi Baou,

Did you manage to resolve this issue? I am running to the same problem. It is nice to know that a previous ROM boots without the screen. I do however wish to run the latest image + 4.14 kernel if possible.

#4

Hi,

Unfortunately no, I don’t have a solution for this and it’s gating migrating to K4.14 on my side. I’m still looking at solutions, if I find something I let you know on this thread.

Cheers.

#5

As I know, we have a temporary solution to boot Android without HDMI connection, which needs to enable virtual frame buffer.

Firstly, need enable kernel configuration:

CONFIG_FB_VIRTUAL=y

Secondly, add additional bootargs in kernel command line:

 video=vfb:640x480-32@30 vfb.videomemorysize=3145728

Please be aware, I tested this method a while back at last year; I don’t test this on the latest code base.

#6

Ideally (and I do note that you specified it as a “temporary solution”), it would be possible to force enable the HDMI using something similar to video=HDMI-A-1:1920x1080@60e (i.e., note the “e” for “force Enable”). The parameter written this way SHOULD be able to force the HDMI port on, as if a monitor were actually connected, even if it isn’t. Being enabled in this manner would allow you to plug in an HDMI monitor later on and have it work.

1 Like
#7

After add ‘video=HDMI-A-1:1920x1080@60e’ into the kernel command line, the Android’s boot_completed flag still will not be set:

console:/ # getprop sys.boot_completed

I can see now HIkey960 support this mode. At beginning, the HDMI port doesn’t attach cable, and later after system boot up I insert HDMI cable and I can see HDMI port is enabled and HDMI monitor can display properly.

I think it is a good suggestion that if kernel command line contains ‘video=HDMI-A-1:1920x1080@60e’, we can enable HDMI always and also can read back ‘sys.boot_completed’ successfully, no matter if really attach HDMI cable or not.

@jstultz, could you take a look for this is good idea or not?

#8

Hi,

Thanks @doitright @leo-yan for your advices.
Interestingly it seemed to work for me (adding video=HDMI-A-1:1920x1080@60e to kernel command line), with no display attached. I get the sys.boot_completed property set and I can see some display init activity in boot log:

My kernel version is 4.14.101-g56136f5a7cad

[ 11.277363] [drm] client change to HDMI
[ 11.283126] [drm] hotplug_event!!!
[ 11.717922] capability: warning: `main’ uses 32-bit capabilities (legacy support in use)
[ 12.475668] [E/hisi_pd] pd_dpm_handle_pe_event:!!!,event=6,+++
[ 12.481547] [I/hisi_pd] pd_dpm_handle_pe_event unkonw event
[ 12.487759] [E/hisi_pd] pd_dpm_handle_pe_event:!!!,event=5,+++
[ 12.493619] Pending event is same → ignore this event 2
[ 12.499160] [E/hisi_pd] pd_dpm_handle_pe_event:!!!,event=3,+++
[ 13.072627] random: crng init done
[ 13.076056] random: 7 urandom warning(s) missed due to ratelimiting
[ 13.321473] healthd: battery none chg=
[ 13.325541] healthd: battery none chg=
[ 13.344080] healthd: battery none chg=
[ 13.448089] [drm] mode->clock(org) = 40000
[ 13.452244] [drm] dss_pxl0_clk = 40000
[ 13.516510] [drm] host attach, client name=[adv7533], id=0
[ 13.538837] [drm] Expected : lane_clock = 320 M
[ 13.543410] [drm] Config : lane_clock = 320000000
[ 13.548131] [drm] PHY clock_lane and data_lane config :
[ 13.548131] rg_vrefsel_vcm=85
[ 13.548131] clk_pre_delay=0
[ 13.548131] clk_post_delay=31
[ 13.548131] clk_t_hs_prepare=3
[ 13.548131] clk_t_lpx=6
[ 13.548131] clk_t_hs_zero=13
[ 13.548131] clk_t_hs_trial=6
[ 13.548131] data_pre_delay=33
[ 13.548131] data_post_delay=0
[ 13.548131] data_t_hs_prepare=4
[ 13.548131] data_t_lpx=6
[ 13.548131] data_t_hs_zero=7
[ 13.548131] data_t_hs_trial=7
[ 13.548131] data_t_ta_go=4
[ 13.548131] data_t_ta_get=5
[ 13.596203] [drm] clk_lane_lp2hs_time=35
[ 13.596203] clk_lane_hs2lp_time=44
[ 13.596203] data_lane_lp2hs_time=59
[ 13.596203] data_lane_hs2lp_time=14
[ 13.596203] phy_stop_wait_time=38
[ 13.613990] [drm] hsa_time=128, hbp_time=88, hline_time=1056
[ 13.619664] [drm] lane_byte_clk=40000000, pixel_clk=40000000
[ 13.625345] [drm] dsi_mipi_init ok

Cheers.

1 Like
#9

That is actually very surprising, since the patch to fix hotplug hasn’t actually been added to the AOSP kernel yet, see https://bugs.96boards.org/show_bug.cgi?id=830 (first post has a patch as attachment). I think the last time I tried that parameter was more than a year ago, and it didn’t work at the time.

I suggest it not so much that it is “a good idea”, but that is actually the specified behavior of that parameter; https://www.kernel.org/doc/Documentation/fb/modedb.txt

1 Like
#10

Excellent.
I’m surprised that it works.

#11

Hi,

Let me refine a bit my answer:
1/ Booting the board without hdmi cable now works till sys.boot_completed assertion, which was my primary intent. Now if I hot-plug the hdmi cable while booted, display remains black, I assume because of mentioned missing hotplug detection patch. But again this is not an issue to me as I have no usage of display in my use cases.

2/ Booting the board with an hdmi cable initially plugged, ends up properly displaying android desktop as expected.

Cheers.

#12

Ah, ok. That’s more consistent with what I would expect.