I bought an Apple mini-DP to VGA adapter. In MacOS (Sierra) it works fine with the VGA adapter provided by the classroom. However, in Linux, no such luck. (It seems the ports are actually "Thunderbolt" but mini-DP compatible.)
Details: the classroom has a Extron device connected to the PC video card which splits the signal to an Extron switchbox and to the PC's monitor (basically a 'Y'). Then, from the switchbox, the cables go across the classroom to a projection system.
When I plug the VGA cable from the PC (cable to the Extron 'Y') Linux detects DP1 just fine, meaning 'xrandr' shows me modes for DP1. However, if I use the VGA cable from the switchbox (which is what IT intends for us to use)...nothing. 'xrandr' thinks DP1 is 'disconnected'. FWIW, Connecting the same mini-DP-VGA adapter directly to a VGA monitor at home, works fine in both Linux and Mac.
As for MacOS...the VGA cable from the switchbox (which IT wants us to use) also works just fine. The problem is only in Linux.
It's a mid-2015 MacBook Pro Retina w/onboard video. 'lspci' says its an "VGA compatible controller: Intel Corporation Crystal Well Integrated Graphics Controller". The onboad 'eDP1' device (Retina display) is fine. I have Debian Jessie installed with a backported kernel (Linux myhost 4.8.0-0.bpo.2-amd64 #1 SMP Debian 4.8.11-1-bpo8+1 (2016-12-14) x86_64 GNU/Linux) to support the Wifi drivers (also giving me a bit 'o' trouble, but that's for another post...)
Any ideas?
TIA.
--C64
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External DP Not Detected on MacBook Pro mid-2015 w/Jessie
- Head_on_a_Stick
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Re: External DP Not Detected on MacBook Pro mid-2015 w/Jessi
I think we need more information:c64whiz wrote:'lspci' says its an "VGA compatible controller: Intel Corporation Crystal Well Integrated Graphics Controller".
Code: Select all
# update-pciids
lspci -nn | grep VGA
https://packages.debian.org/jessie-back ... sc-nonfree
Or perhaps a newer graphics stack will help:
https://forums.bunsenlabs.org/viewtopic.php?id=1185
deadbang
Re: External DP Not Detected on MacBook Pro mid-2015 w/Jessi
This is definitely a path I've not tried and am anxious to (especially the xorg-intel package from Backports!). I won't be able to play with the kernel until this weekend (I want to image the drive in case something goes wrong).
On the Skylake matter, is there way to tell if it is a Skylake device (or not)?
Thank again!!
--C64
On the Skylake matter, is there way to tell if it is a Skylake device (or not)?
Thank again!!
--C64
- Head_on_a_Stick
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Re: External DP Not Detected on MacBook Pro mid-2015 w/Jessi
c64whiz wrote:is there way to tell if it is a Skylake device (or not)?
I wrote:Code: Select all
# update-pciids lspci -nn | grep VGA
deadbang
Re: External DP Not Detected on MacBook Pro mid-2015 w/Jessi
Duh, sorry. Although I still don't know if I have a Skylake processor. The 'lspci -nn' returns:
Also, I added the additional/new Graphic stack. I'll have to test later this week.
Will let you know, and thanks for the help.
--C64
Code: Select all
00:02.0 VGA compatible controller [0300]: Intel Corporation Crystal Well Integrated Graphics Controller [8086:0d26] (rev 08)
Will let you know, and thanks for the help.
--C64
Re: External DP Not Detected on MacBook Pro mid-2015 w/Jessi
Apparently I left this unanswered and I don't like that. So my apologies for the really late response, but the solution to the VGA adapter not working was power. Yes, as in electricity. For some reason, the MBP did not put out enough juice through the VGA for it to show up properly. Once I bought an HDMI to VGA adapter which uses it's own power source via micro-usb, VGA display worked fine.