+People in community. Rodrigo, Thanks for the kind info. What's the answer to below question? I find i915 binds one pipeline per display. It means even with DP1.2 MST, i915 driver still restricts the display number to the display pipeline number. Am I right? In addition, I might mislead you at case 1). The NUC has 1 HDMI interface and 1 USB type-C interface. I connect a display by HDMI to that HDMI interface. Then, I connect other 2 displays by the CE-LINK box which connect to the usb type-C interface. Yanmin > -----Original Message----- > From: Vivi, Rodrigo > Sent: Tuesday, December 04, 2018 6:28 AM > To: Zhang, Yanmin <yanmin.zhang@xxxxxxxxx> > Cc: Syrjala, Ville <ville.syrjala@xxxxxxxxx> > Subject: Re: DP1.2 MST HUB > > Hi there, > > again, please ask these questions in public mailing lists. > > On Sun, Dec 02, 2018 at 06:43:31PM -0800, Zhang, Yanmin wrote: > > Here is the result. > > > > 1) If I use a CE-LINK 1-to-2 converter, 1usb type-C in, and 2 HDMI out, it works > with my NUC. This NUC has 1 HDMI and 1 USB type C interfaces. > > a) If I connect 1 display by HDMI, and other 2 displays by the CE-LINK, > android refuses (logcat shows No permission) to show application GUI to the 3rd > display. It might be an issue of Android. > > b) If I remove HDMI display, but just connect other 2 displays by CE-LINK, > both displays can work. > > > > 2) If I use CLUB-3D box which has 1 DP in and 4 DP out, I have to use a usb type- > C to DP cable, then connect to a DP converter with 2 daughter interfaces, then > connect to the CLUB-3D, then to 2 displays. Kernel driver reports the displays, but > the display is always black. Perhaps there are too many converters on the > connection path. > > If I use CLUB-3D box to connect to my desktop which uses NEVIDE display card, > it works well. > > > > > > At 1).b) case, I find i915 binds one pipeline per display. It means even with > DP1.2 MST, i915 driver still restricts the display number to the display pipeline > number. Am I right? Can we extend display number more than pipeline number? > > I'm not sure if I followed your case here, but 2 things here: > > 1. it seems that > you might be reached the maximun number of allocated vcpi here. > > Just by leaving cable connected the vpci gets reserved on drm if I remember > correctly so things might not fully work. > > But it is hard to tell without any log. if that is the case. > > 2. About the "extend display part" there is currently a limitation of the vertical > size that Ville was working to solve that. > I'm not sure about the status. > > Thanks, > Rodrigo. > > > > > Thanks, > > Yanmin > > > > > -----Original Message----- > > > From: Zhang, Yanmin > > > Sent: Friday, November 30, 2018 8:24 AM > > > To: Vivi, Rodrigo <rodrigo.vivi@xxxxxxxxx> > > > Cc: Syrjala, Ville <ville.syrjala@xxxxxxxxx> > > > Subject: RE: DP1.2 MST HUB > > > > > > Rodrigo, > > > > > > Thanks for the kind info. 'enabling' here is to check if DP1.2 MST > > > (perhaps with > > > HBR2) can work with intel NUC (with type-C DP). Later on, check it > > > on new IVE system which might be based on ElkhartLake or Tigerlake. > > > If it doesn't work, I have to check if it's about either MST HUB > > > hardware, or software such like i915 driver. Basically, I am not > > > i915 driver expert, but I assume you guys already enabled it well. > > > > > > I already ordered a MST HUB https://www.club- > > > 3d.com/en/detail/2411/multi_stream_transport_(mst)_hub_displayportt_ > > > 1.2_qu ad_monitor/, and another one which has an input of USB Type-C > > > and 2 HDMI outputs. > > > Hope it can work. > > > > > > Even when it works, IVE system might not use the MST HUB directly. I > > > suppose IVE hardware architect will use specific AIC to implement > > > MST HUB capability on board. Currently, I want to prove DP 1.2 MST can work > well on Intel chips. > > > > > > I will keep you guys posted. > > > > > > Yanmin > > > > > > > -----Original Message----- > > > > From: Vivi, Rodrigo > > > > Sent: Friday, November 30, 2018 1:45 AM > > > > To: Zhang, Yanmin <yanmin.zhang@xxxxxxxxx> > > > > Cc: Syrjala, Ville <ville.syrjala@xxxxxxxxx> > > > > Subject: Re: DP1.2 MST HUB > > > > > > > > Hi Yanmin, > > > > > > > > On Wed, Nov 28, 2018 at 05:03:02PM -0800, Zhang, Yanmin wrote: > > > > > Dear GFX/display experts, > > > > > > > > maybe it would be probably good to ask to dri-devel and/or > > > > intel-gfx at lists.freedesktop.org > > > > > > > > > > > > > > > > > > > Would you like to share some info about MST HUB? I am enabling > multiple > > > > > display support by MST. > > > > > > > > What do you mean by "enabling" here? > > > > > > > > > > > > > > > > > > > 1) Currently, I have a KBL NUC which has a USB-Type C port. By a > > > > > USB Type-C to DP cable, it connect to a display panel and it can work > > > > > well. KBL NUC prod spec says it can extend to connect multiple displays > > > > > by DP1.2 MST. What MST HUB should be used? > > > > > > > > short answer: Any dongle that supports DP1.2 MST. > > > > > > > > However dongles can have firmware doing non compliant things that > > > > could cause headaches. So I'd recommend to get one that is know to > > > > have a > > > good quality. > > > > Unfortunately I don't have any one specific to recommend. > > > > > > > > > > > > > > 2) If I buy a HUB like > > > > > > > > > > > > [1]https://item.taobao.com/item.htm?spm=a230r.1.14.110.32f348d5JPpMM > > > s& > > > > i > > > > > d=43812089455&ns=1&abbucket=17#detail , can I use that type-C to DP > > > > > conversion cable to connect to the HUB and MST still works? > > > > > > > > > > How about [2]http://item.jd.com/10210412498.html? > > > > > > > > > > > > > > > 3) Can I use another simple HUB like > > > > > [3]http://item.jd.com/28683591806.html? > > > > > > > > > > > > > > > Above links have Chinese characters, but the pictures and some English > > > > > text are clear. > > > > > > > > Well, first link doesn't work and I couldn't extract any useful > > > > information from the english parts. But if they implement DP MST > > > > properly it > > > should just work. > > > > > > > > > > > > > > > > > > > Would you like to give me your expert comments on that? > > > > > > > > try it out and let me know if it works :P > > > > > > > > Cheers, > > > > Rodrigo. > > > > > > > > > > > > > > > > > > > Thanks, > > > > > > > > > > Yanmin > > > > > > > > > > References > > > > > > > > > > 1. > > > > > > > https://item.taobao.com/item.htm?spm=a230r.1.14.110.32f348d5JPpMMs&i > > > d= > > > > 4 > > > > 3812089455&ns=1&abbucket=17#detail > > > > > 2. http://item.jd.com/10210412498.html > > > > > 3. http://item.jd.com/28683591806.html _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
