Planet USB-C to HDMI Video Cable

[RonWard]

What are the specs and is there an alternate to the PC one?    USB C (which version) and female HDMI (which version) and has PC connected standard?

[Daniel W]

While only a partial answer, Planet has stated that MediaTek, the company making the SoC for the Planet devices, uses a proprietary non-standard solution to output HDMI via a USB type C connector, which means a standard HDMI alt mode USB type-C to HDMI cable will not work.

Though I do have a Planet HDMI cable, I don't have proper equipment to examine how the pins are connected. As I suppose the cable offered by Planet is MediaTek-specific rather than Planet-specific, maybe an USB type-C to HDMI cable for some other phone, based on a MediaTek SoC could work, provided any other phone maker, using MediaTek chips, supports HDMI out.

I doubt the exact USB and HDMI versions matters much. On the Gemini and Cosmo, the HMDI out can only output their native resolution of 2160x1080 and only at 60p. A qualified guess would be that the Astro will also only output its native resolution (2340x1080) at 60p. While the aspect ratio is odd, which might affect display compatibility, the required bitrate should fit within the HDMI 1.0 specification of (from 2002).

There are a few threads here on OESF mentioning a "USB-C to HDMI DisplayLink" (not to be confused with DisplayPort) adapter. DisplayLink seems to be an external graphics chip, thus requiring an app to work. As I don't have any particular knowlege to share, I can only recommend, should you be interested, that you use the search feature, in the top right corner and read what others has to say.

[RonWard]

Thank you

[Zarhan]

Yes - the fact that resolution is nonstandard is a problem. E.g. I cannot get the Cosmo picture to appear on our LG OLED TV, while it does work with my PC monitor.

It really should be selectable.

[abliss]

I tried the PC USB-to-HDMI adapter from my Cosmo, and it doesn't seem to work on the Astro. I noticed that the indiegogo page claimed "USB to DisplayPort"  rather than HDMI, so maybe it'll be a new cable.

[gymbo]

I tried the PC USB-to-HDMI adapter from my Cosmo, and it doesn't seem to work on the Astro. I noticed that the indiegogo page claimed "USB to DisplayPort"  rather than HDMI, so maybe it'll be a new cable.

From what I've read it is SUPPOSED to be the same cable, but remember that it is (at least was) also only supposed to work on the right side USB...

I also seem to remember that people where able to get HDMI out from Gemini/Cosmo by using a USB to DisplayPort (and then DisplayPort to HDMI)??

[abliss]

I looked at a dmesg dump from my Cosmo while plugging in the hdmi adapter:

[Thu Jan 16 15:19:08 2020]  (0)[24744:kworker/0:1]====fusb300_eint_work:zhaolong debug x600 USB1=====
[Thu Jan 16 15:19:08 2020]  (0)[24744:kworker/0:1]===USB1 is plug in===
[Thu Jan 16 15:19:08 2020]  (0)[24744:kworker/0:1]===hdmi plug in===
[Thu Jan 16 15:19:08 2020]  (0)[24744:kworker/0:1]=======CC2=======
[Thu Jan 16 15:19:09 2020]  (0)[162:hdmi_timer_kthr]i2c i2c-3: addr: 39, transfer ACK error
[Thu Jan 16 15:19:09 2020]  (0)[162:hdmi_timer_kthr]i2c_dump_info ++++++++++++++++++++++++++++++++++++++++++
[Thu Jan 16 15:19:09 2020]  (0)[162:hdmi_timer_kthr]I2C structure:
[Thu Jan 16 15:19:09 2020] [I2C]Clk=15600,Id=3,Op=1,Irq_stat=2,Total_len=2
[Thu Jan 16 15:19:09 2020] [I2C]Trans_len=2,Trans_num=1,Trans_auxlen=0,speed=400000
[Thu Jan 16 15:19:09 2020] [I2C]Trans_stop=1
[Thu Jan 16 15:19:09 2020]  (0)[162:hdmi_timer_kthr]base address 0xffffff8004e26000
[Thu Jan 16 15:19:09 2020]  (0)[162:hdmi_timer_kthr]I2C register:
[Thu Jan 16 15:19:09 2020] [I2C]SLAVE_ADDR=72,INTR_MASK=f8,INTR_STAT=1,CONTROL=28,TRANSFER_LEN=2
[Thu Jan 16 15:19:09 2020] [I2C]TRANSAC_LEN=1,DELAY_LEN=2,TIMING=13,START=2,FIFO_STAT=2201
[Thu Jan 16 15:19:09 2020] [I2C]IO_CONFIG=3,HS=0,DCM_EN=0,DEBUGSTAT=40,EXT_CONF=1800,TRANSFER_LEN_AUX=1
[Thu Jan 16 15:19:09 2020]  (0)[162:hdmi_timer_kthr]before enable DMA register(0x0):
[Thu Jan 16 15:19:09 2020] [I2C]INT_FLAG=0,INT_EN=0,EN=0,RST=0,
[Thu Jan 16 15:19:09 2020] [I2C]STOP=0,FLUSH=0,CON=0,TX_MEM_ADDR=0, RX_MEM_ADDR=0
[Thu Jan 16 15:19:09 2020] [I2C]TX_LEN=0,RX_LEN=0,INT_BUF_SIZE=0,DEBUG_STATUS=0
[Thu Jan 16 15:19:09 2020] [I2C]TX_MEM_ADDR2=0, RX_MEM_ADDR2=0
[Thu Jan 16 15:19:09 2020]  (0)[162:hdmi_timer_kthr]DMA register(0xffffff8004e28480):


When plugging into my astro, I get no such messages. So unless they quieted them (doubtful--the rest of dmesg is as noisy as ever), I suspect that HDMI output on astro may require kernel work that is not yet included in the released builds.


Edit to add: there's also this part in logcat:

10-07 20:40:11.444  1073  1283 I HdmiObserver: HdmiObserver: onUEvent: {SUBSYSTEM=switch, SEQNUM=5460, ACTION=change, SWITCH_NAME=otg_state, DEVPATH=/devices/virtual/switch/otg_state, SWITCH_STATE=1}
10-07 20:40:11.444  1073  1283 I HdmiObserver: HdmiObserver.onUEvent(), name=otg_state, state=1
10-07 20:40:11.444  1073  1283 I HdmiObserver: HDMIObserver.updateOtgState(), otgState=1
10-07 20:40:11.444  1073  1333 I HdmiObserver: HDMIObserver.handleOtgStateChanged(), otgState=1
10-07 20:40:11.445  1073  1333 E hdmi    : =====hdmi===== [HDMI] [hdmi_ioctl] open hdmitx. fd=207 cmd_code=-1073461215
10-07 20:40:11.445  1073  1333 I HdmiObserver: notifyOtgState: true
10-07 20:40:11.458  1073  1424 I UsbDescriptorParser: Unknown Descriptor len: 6 type:0x30

So, if it is indeed the same cable, the missing software could be kernel-side or userspace-side.

Another observation:  if I run "getevent" on the cosmo, when I plug the HDMI adapter in, I see the following from "mtk-kpd":

/dev/input/event1: 0001 00b8 00000001
/dev/input/event1: 0000 0000 00000000
/dev/input/event1: 0001 00b8 00000000
/dev/input/event1: 0000 0000 00000000

meanwhile I get nothing at all while plugging into the astro.

Astro's kernel tree has in drivers/misc/mediatek/typec/fusb302 some hdmi-plugging code that seems similar to what the cosmo had in drivers/misc/mediatek/usb_c/fusb302 , and the device shows up similarly in /sys/devices/platform/fusb301a... 

[RonWard]

The IGG states its USB-HDMI? 

I tried the PC USB-to-HDMI adapter from my Cosmo, and it doesn't seem to work on the Astro. I noticed that the indiegogo page claimed "USB to DisplayPort"  rather than HDMI, so maybe it'll be a new cable.

[cam1965]

I wrote to the PC asking if the cosmo cable is the same as the astro cable or if it's a software problem. There are still no answers.

[RonWard]

I wrote to the PC asking if the cosmo cable is the same as the astro cable or if it's a software problem. There are still no answers.

Have never had a reply from PC on AstroSlide 5G questions and have also asked that they consider adding AstroSlide 5G to there Support site.  No reply!!!!

[cam1965]

Hdmi works partially using the hdmi cable from cosmo and connected at the  left side of astro.. You must connect the cable and do a restart. After this, the display output is only in the TV, not in the display of astro. I connected a mouse to work with the phisycal keyboard and the display of TV. Sound after some time is distorced.  I tried to attach a video here that I have made using my cosmo but it was not successful.

[cam1965]

Link to video . Sorry for the quality of video.
https://youtu.be/QMCLxmedJlc

[cam1965]

I also don't know if astro has support to usb dp alt mode. I have tested an hp usb c to hdmi  dp alt mode   adapter and it does' t  work.

[abliss]

Wow, thanks cam1965, excellent discovery! How did you figure that out?

I've been poking at the kernel source. It seems that there's some partial support for standard usb type c alternate-mode displayport. I tried 2 displays and 3 adapters/cables. In all cases, dmesg indicates a successful negotiation with the display and the astro adopts Downstream Facing Port mode. But nothing appears on the screen and no new device shows up in /sys/class/drm . (With a usb-c cable to a usb-c display, I was able to get the Astro charging over usb-pd and also using the screen's usb hub at the same time, which Cosmo was never able to do.) The code seems to suggest that a PI3DPX1205A chip is required to activate DisplayPort, but that driver isn't in the astro's device tree (k6873v1_64.dts). I wonder if the Astro indeed has this chip, and if so, how it's wired up.

[abliss]

I have a hunch about why the hdmi adapter only works if plugged in on boot. In the astro kernel tree, drivers/misc/mediatek/typec/fusb302 has code very much like the cosmo's hdmi plug detection code. It exports a symbol, hdmi_plug_in_flag, which gets changed to 1 when the port detects the adapter and 0 when the adapter is removed. However, unlike in the Cosmo tree, this variable is never used. It is however mentioned in commented-out code in drivers/gpu/drm/panel-vt-lt8912b-vdo.c . This driver is part of astro's device tree. In its .probe function, it calls FUSB300Read to check if the adapter is plugged in, and if so, sets the gpios necessary to send HDMI out. However, this probe function is only called once, at boot-up time.

Cosmo had a device at /dev/hdmitx and some userspace daemon for managing the hdmi output through ioctls on that device. Some similar code remains in the astro tree but it is not enabled in the device tree.

So, thanks to cam1965's discovery, I suspect we may be able to fix up Astro's proprietary left-side hdmi-output with some small changes. (I would be much happier if we could get standard displayport altmode working though!)