[HDMI plug tests] Access even HDMI screen is OFF (Xvnc APKG for ex.)
Posted: Sun Apr 17, 2016 8:20 pm
HI,
This is a short information about tests I have done to access my ASUSTOR Applications (Asportal, Desktop_Engine, etc.) using HDMI screen when the screen is disconnected
ATTENTION not sure this also work for you ... depend of context, hardware and link ... so just to share with you
feel free to share also your own experience ...
Test platforms :
AS5002T (1080P)
TV Samsung D5700
Monitor (with sound) BENQ senseye3
Problem :
When HDMI screen is disconnected ... and you use a remote connection to access Asportal (ex. using XVncServer Community APKG) or the Ubuntu Desktop from "Desktop Engine" (XVncServer APKG or any Vnc server inside the Ubuntu chroot) YOU MUST have problem due to the fact that HDMI can appear as disconnected or with invalid resolution to use Vnc Client
Solutions :
A) It's always possible to play with xrandr to manage a false frame buffer size or generate false mode and virtual screen
... BUT first it's not easy ... two in lot of case this can be break by any program reallocating xrandr AND if your program need to have sound configured (even you can't hear the sound (except specific pulseaudio usage) from remote ... BUT it's not the purpose ... of this topic) sometimes program refuse to start ...
B) a good solution is a HDMI Plug that reply to EDID request from Xserver and deliver valid information ... and support (even fake) the DCC/CI interface
EDID VESA provide (shortly) :
... name of the screen provide ... product name ... video format supported (1080P, 1080I, etc. ) ... audio format supported ... color depth ... etc.
DCC/CI
... is a set of command use by Xserver (ex. brightness, contrast, etc. )
B 1 )
PASSIVE HDMI PLUG :
This plug are "plugged" directly to the back of the Asustor and REPLACE the HDMI cable
tested models :
Compute-lab FIT Headless (support full HD or (another model 4K) definition) : work as expected ... EDID returned is correct screen appear to be "connected" sound supported
... application using xrandr (like kodi) can be launched remotely, idem for Chrome and other tools fillezilla, etc.
FOR this solution :
... FullHD work as well
CONS. :
... need to disconnect HDMI cable ... so if another person want to use it ... localy ... need a manipulation (clearly a problem if the NAS is in a cabinet for ex.)
B 2 )
ACTIVE PASS-THROUGH PLUG :
This plug are installed at the back of the NAS and have a female plug to put the ordinary cable ... so the real TV or screen keep connected ..
some plug propose a standard VESA response ... some other can be "programmed" to clone the screen definition ...
tested model :
HDMI Lindy 32103 emulator adapter with standard definition for FullHD (even last model support 4K after programmation)
CASE 1 : without clonage ...
... Work as a PASSIVE plug + you have a correct image ... BUT NO SOUND
... ... NO sound and NO error ... the plug said that sound exist but without valid value ... so this generate NO ERROR ... BUT NO sound
... ... so it's not the target expected ... keeping the local access without having to do somethings locally ...
CASE 2 after clonage ... to clone I have use the Lindy 32100 Emulator programmer (hum! a cost for a unique use (not for me but for standard user) )
... after cloning my TV screen value ( in fact all is done in less of 2 minutes)
... ALL WORK as expected ... SOUND, Asustor see the plug exactly as the TV ... same sound definition and screen resolution are available ... and keep it even screen is OFF
... ... AND the TV can be use as well
... ... BIGGEST advantage ... the cable after the plug can be long, can be use Ethernet extender or what else when in real case it don't work (Asustor don't receive correct EDID) ... so it's really an amazing solution ...
... ... programmer support also 4K ...
... ... also interesting to be used with AUDIO player interfaced by HDMI ... to get the best visibility of the twice (Sound from player + TV definition)
FOR this solution :
CLEARLY ONLY if you use the programmer ... it's the full good result ...
... add possibility to have long space between the Asustor and the screen, accept any kind of extender ...
IN native mode ... it's like the passive model ...
CONS. :
... need to buy the programmer (if nobody can lend you ... one for 5 minutes)
Please don't hesitate to add here your OWN experience.
Philippe.
This is a short information about tests I have done to access my ASUSTOR Applications (Asportal, Desktop_Engine, etc.) using HDMI screen when the screen is disconnected
ATTENTION not sure this also work for you ... depend of context, hardware and link ... so just to share with you
feel free to share also your own experience ...
Test platforms :
AS5002T (1080P)
TV Samsung D5700
Monitor (with sound) BENQ senseye3
Problem :
When HDMI screen is disconnected ... and you use a remote connection to access Asportal (ex. using XVncServer Community APKG) or the Ubuntu Desktop from "Desktop Engine" (XVncServer APKG or any Vnc server inside the Ubuntu chroot) YOU MUST have problem due to the fact that HDMI can appear as disconnected or with invalid resolution to use Vnc Client
Solutions :
A) It's always possible to play with xrandr to manage a false frame buffer size or generate false mode and virtual screen
... BUT first it's not easy ... two in lot of case this can be break by any program reallocating xrandr AND if your program need to have sound configured (even you can't hear the sound (except specific pulseaudio usage) from remote ... BUT it's not the purpose ... of this topic) sometimes program refuse to start ...
B) a good solution is a HDMI Plug that reply to EDID request from Xserver and deliver valid information ... and support (even fake) the DCC/CI interface
EDID VESA provide (shortly) :
... name of the screen provide ... product name ... video format supported (1080P, 1080I, etc. ) ... audio format supported ... color depth ... etc.
DCC/CI
... is a set of command use by Xserver (ex. brightness, contrast, etc. )
B 1 )
PASSIVE HDMI PLUG :
This plug are "plugged" directly to the back of the Asustor and REPLACE the HDMI cable
tested models :
Compute-lab FIT Headless (support full HD or (another model 4K) definition) : work as expected ... EDID returned is correct screen appear to be "connected" sound supported
... application using xrandr (like kodi) can be launched remotely, idem for Chrome and other tools fillezilla, etc.
FOR this solution :
... FullHD work as well
CONS. :
... need to disconnect HDMI cable ... so if another person want to use it ... localy ... need a manipulation (clearly a problem if the NAS is in a cabinet for ex.)
B 2 )
ACTIVE PASS-THROUGH PLUG :
This plug are installed at the back of the NAS and have a female plug to put the ordinary cable ... so the real TV or screen keep connected ..
some plug propose a standard VESA response ... some other can be "programmed" to clone the screen definition ...
tested model :
HDMI Lindy 32103 emulator adapter with standard definition for FullHD (even last model support 4K after programmation)
CASE 1 : without clonage ...
... Work as a PASSIVE plug + you have a correct image ... BUT NO SOUND
... ... NO sound and NO error ... the plug said that sound exist but without valid value ... so this generate NO ERROR ... BUT NO sound
... ... so it's not the target expected ... keeping the local access without having to do somethings locally ...
CASE 2 after clonage ... to clone I have use the Lindy 32100 Emulator programmer (hum! a cost for a unique use (not for me but for standard user) )
... after cloning my TV screen value ( in fact all is done in less of 2 minutes)
... ALL WORK as expected ... SOUND, Asustor see the plug exactly as the TV ... same sound definition and screen resolution are available ... and keep it even screen is OFF
... ... AND the TV can be use as well
... ... BIGGEST advantage ... the cable after the plug can be long, can be use Ethernet extender or what else when in real case it don't work (Asustor don't receive correct EDID) ... so it's really an amazing solution ...
... ... programmer support also 4K ...
... ... also interesting to be used with AUDIO player interfaced by HDMI ... to get the best visibility of the twice (Sound from player + TV definition)
FOR this solution :
CLEARLY ONLY if you use the programmer ... it's the full good result ...
... add possibility to have long space between the Asustor and the screen, accept any kind of extender ...
IN native mode ... it's like the passive model ...
CONS. :
... need to buy the programmer (if nobody can lend you ... one for 5 minutes)
Please don't hesitate to add here your OWN experience.
Philippe.