Invalid Display, HP monitor sends only 80 80 be 6e 6e bytes over I2C

[capi1O]

I try to control the brightness of my HP monitor HP 27es (codename HWP3325), pluged in HDMI port of Asus Laptop (UX310). I tried both HDMI ports on the monitor (it was suggested by gddccontrol utility, which did not work on the first port. ddcutil reports same output on both ports).

DDC/IC enabled in OSD.

ddcutil detect reports Invalid Display :

Invalid display
   I2C bus:             /dev/i2c-0
   Supports DDC:        true
   EDID synopsis:
      Mfg id:           HWP
      Model:            HP 27es
      Serial number:    3CM7240ZLG   
      Manufacture year: 2017
      EDID version:     1.3
   DDC communication failed

if --ddc is enabled the following is visible :

DDC: Unexpected source address 0x80, should be 0x6e
DDC: i2c_response_bytes: 80 80 be 6e 80 be 6e 6e 80 be 00 6e 80 be 6e 80 be 6e 6e 80
DDC: Unexpected source address 0xbe, should be 0x6e
DDC: i2c_response_bytes: be 00 6e 80 be 6e 80 be 6e 80 be 6e 80 be 6e 80 be 6e 6e 80
DDC: Unexpected source address 0xbe, should be 0x6e
DDC: i2c_response_bytes: be be 6e 80 be 6e 80 be 6e 80 80 be 6e 6e 80 be 6e 80 be 6e
DDC: Unexpected source address 0x80, should be 0x6e
DDC: i2c_response_bytes: 80 80 be 00 6e 80 be 6e 80 be 00 6e 80 be 6e 80 be 6e 6e 80
DDC: Unexpected source address 0xbe, should be 0x6e
DDC: i2c_response_bytes: be 00 6e 80 be 6e 6e 80 be 6e 80 be 6e 6e 80 be 6e 80 80 be
DDC: Double byte in packet.
DDC: i2c_response_bytes: 6e 6e 80 be 6e 6e 80 be 6e 80 be 6e 80 be 6e 80 be 6e 80 be
DDC: Double byte in packet.
DDC: i2c_response_bytes: 6e 6e 80 be 6e 6e 80 be 6e 80 be 6e 80 be 6e 80 be 6e 6e 80
DDC: Unexpected source address 0xbe, should be 0x6e
DDC: i2c_response_bytes: be 00 6e 80 be 6e 80 be 6e 80 80 be 6e 80 be 6e 80 be 00 6e
DDC: Unexpected source address 0x80, should be 0x6e
DDC: i2c_response_bytes: 80 80 be 6e 6e 80 be 6e 80 be 00 6e 80 be 6e 80 be 6e 6e 80
DDC: Unexpected source address 0xbe, should be 0x6e
DDC: i2c_response_bytes: be 00 6e 80 be 6e 80 be 6e 80 be 6e 80 be 6e 80 be 6e 6e 80

It looks like the bytes received are shifted (ddcutil expects 0x6e but reads 0x80 whereas next byte is 0x6e).

ddcutil 0.8.6 on Ubuntu 17.10 (wayland) for what it worth.

ddcutil detect --verbose --ddc --force-slave-address >> ddcutil-detect.txt ddcutil environment --verbose --ddc --force-slave-address >> ddcutil-environment.txt

[rockowitz]

Thank you for the detailed report. Unfortunately, I don't have very good news.   The I2C communication with the monitor is garbled.  Some monitors are just dirty.   I'll add the HP 27es to the rogues gallery at www.ddcutil.com/monitor_notes.

Have you tried plugging in a different monitor for testing? Alternatively, have you tried running ddcutil with this monitor on another system?

It doesn't appear that your laptop is docked.  But if it is, try using a non-dock connection.  There are problems with the i915 driver when using a docking station.

Try the undocumented option "--sleep-strategy 2", aka "-y 2". This doubles the time that ddcutil sleeps over that required by the DDC/CI spec.  Occasionally this helps.

Lastly, when submitting reports in the future, please use the "--verbose" and "--stats" options.

Sanford

On 02/02/2018 11:09 AM, monkeydri wrote:

I try to control brightness of my HP monitor HP 27es (codename HWP3325), pluged in HDMI port of Asus Laptop (UX310). I tried both HDMI ports on the monitor (it was suggested by gddccontrol utility, which did not work on the first port. ddcutil reports same output on both ports).

DDC/IC enabled in OSD.

ddcutil detect reports Invalid Display :

|ddcutil detect --verbose --ddc --force-slave-address Output level: Verbose Reporting DDC data errors: true Trace groups active: none Traced functions: none Traced files: none Force I2C slave address: true DDC: Unexpected source address 0x80, should be 0x6e DDC: i2c_response_bytes: 80 80 be 6e 6e 80 be 6e 80 be 00 6e 80 be 6e 80 be 6e 6e 80 DDC: Unexpected source address 0xbe, should be 0x6e DDC: i2c_response_bytes: be 00 6e 80 be 6e 80 be 6e 80 be be 6e 6e 80 be 6e 80 be be DDC: Double byte in packet. DDC: i2c_response_bytes: 6e 6e 80 be 6e 80 be 6e 80 be 00 6e 80 be 6e 80 be 6e 6e 80 DDC: Unexpected source address 0xbe, should be 0x6e DDC: i2c_response_bytes: be 00 6e 80 be 6e 80 be 6e 80 be be 6e 80 be 6e 80 be 00 6e DDC: Unexpected source address 0x80, should be 0x6e DDC: i2c_response_bytes: 80 80 be 6e 80 be 6e 80 be 6e 80 80 be 6e 80 be 6e 80 be 6e DDC: Unexpected source address 0x80, should be 0x6e DDC: i2c_response_bytes: 80 80 be 6e 6e 80 be 6e 6e 80 be be 6e 6e 80 be 6e 80 be be DDC: Double byte in packet. DDC: i2c_response_bytes: 6e 6e 80 be 6e 80 be 6e 80 be 00 6e 80 be 6e 80 be 6e 80 be DDC: Double byte in packet. DDC: i2c_response_bytes: 6e 6e 80 be 6e 6e 80 be 6e 80 be be 6e 6e 80 be 6e 80 be be DDC: Double byte in packet. DDC: i2c_response_bytes: 6e 6e 80 be 6e 80 be 6e 80 be 00 6e 80 be 6e 80 be 6e 80 be DDC: Double byte in packet. DDC: i2c_response_bytes: 6e 6e 80 be 6e 80 be 6e 80 be 00 6e 80 be 6e 80 be 6e 80 be Invalid display I2C bus: /dev/i2c-0 Supports DDC: true I2C address 0x30 (EDID block#) present: false I2C address 0x37 (DDC) present: true I2C address 0x50 (EDID) present: true /sys/bus/i2c/devices/i2c-0/name: i915 gmbus dpc EDID synopsis: Mfg id: HWP Model: HP 27es Serial number: 3CM7240ZLG Manufacture year: 2017 EDID version: 1.3 Product code: 0x3326 (13094) Extra descriptor: Unspecified Video input definition: 0x80 - Digital Input Supported features: DPMS active-off Digital display type: RGB 4:4:4 Standard sRGB color space: False White x,y: 0.312, 0.328 Red x,y: 0.652, 0.337 Green x,y: 0.319, 0.611 Blue x,y: 0.149, 0.067 Extension blocks: 1 EDID source: EDID hex dump: +0 +4 +8 +c 0 4 8 c +0000 00 ff ff ff ff ff ff 00 22 f0 26 33 01 00 00 00 ........".&3.... +0010 18 1b 01 03 80 3c 22 78 2a 1e 50 a7 56 51 9c 26 .....<"x*.P.VQ.& +0020 11 50 54 a1 08 00 d1 c0 b3 00 a9 c0 95 00 81 80 .PT............. +0030 81 00 81 c0 01 01 02 3a 80 18 71 38 2d 40 58 2c .......:..q8-@X, +0040 45 00 56 50 21 00 00 1e 00 00 00 fd 00 32 3c 1e E.VP!........2<. +0050 50 11 00 0a 20 20 20 20 20 20 00 00 00 fc 00 48 P... .....H +0060 50 20 32 37 65 73 0a 20 20 20 20 20 00 00 00 ff P 27es. .... +0070 00 33 43 4d 37 32 34 30 5a 4c 47 20 20 20 01 38 .3CM7240ZLG .8 DDC communication failed Is DDC/CI enabled in the monitor's on-screen display? |

ddcutil 0.8.6 on Ubuntu 17.10 (wayland) for what it worth.

ddcutil-detect.txt https://github.com/rockowitz/ddcutil/files/1689946/ddcutil-detect.txt ddcutil-environment.txt https://github.com/rockowitz/ddcutil/files/1689947/ddcutil-environment.txt

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[capi1O]

Thank you very much for your answer.

I tried the option --sleep-strategy 2 but no success. I also plugged it to another computer with the same result. I have no other HDMI monitor to try.

I plan to plug the monitor to a windows computer through a HDMI breakout board with an I2C USB sniffer (I happen to own a saleae logic analyzer), because there is a HP tool on windows which is able to control brightness and other settings, so there is certainly a way to do it.

I will let you know once its done, thanks again !

[rockowitz]

Do let me know what you find with the logic analyzer.   I would not be surprised to find that the tolerances are marginal - good enough for the Windows driver, which appears to be more sophisticated than what is available on Linux.   It's also likely that monitor testing occurs on Windows, not on Linux.

You might want to install EnTech's softMCCS utility for Windows. EnTech is a make of DDC chipsets, and softMCCS is their utility for exercising the full protocol.

Short of writing my own I2C drivers, there's not much that ddcutil can do to tweak the I2C layer.  And therein lies maintenance madness.

Sanford

On 02/05/2018 09:48 AM, monkeydri wrote:

Thank you very much for your answer.

I tried the option |--sleep-strategy 2| but no success. I also plugged it to another computer with the same result. I have no other HDMI monitor to try.

I plan to plug the monitor to a windows computer through a HDMI breakout board with an I2C USB sniffer (I happen to own a saleae logic analyzer), because there is a HP tool on windows which is able to control brightness and other settings, so there is certainly a way to do it.

I will let you know once its done, thanks again !

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