my first start with Neo begins with a black Screen. I use a "mirco HDMI to HDMI" and "HDMI to DVI adapter" The Screen will turn on but then is black. The TV Screen with HDMI is running good. The same problem was to begin with the Raspberry Pi and fixed with config.txt hdmi_force_hotplug=1 and my UDOO Dual runs since two years with HDMI-DVI adapter.
I found this. https://community.freescale.com/thread/309202 and https://boundarydevices.com/dvi-support-on-i-mx6-boards/ It is also a problem with UDOOBuntu Beta3.
For what regards Neo the situation is a bit harder because the i.MX 6SoloX processor does not support HDMI directly. We have a chip, TDA1998, that cares about this. We'll try the boundary patch you send us, but it's not given that it will work. Have you tried it first?
I don't understand why changing the TDA1998 chip to output DVI it is hard(er). In fact the data sheet for the part says that it defaults to DVI and must be programmed to output HDMI. It looks like the uEnv.txt file which already has video_output=hdmi would be the ideal place to select which output to use.
That is to choose the output between hdmi and lvds7 That way you choose the right device tree to load at boot. For HDMI - DVI , I think @jas-mx can explain this better (would you, @jas-mx?).
"That is to choose the output between hdmi and lvds7" "That way you choose the right device tree to load at boot." Fine, find some place else to put it or give it its own device tree (may have to do that anyway ?) and add that as an option along with the other two. I had to buy an HDMI monitor mostly because of this (see Orange Pi below). Most of the other ARM SBC's I have Raspberry Pi (A, B, B+, 2B+), Banana Pi, CubieBoard 1, ODROID-C1 work with both although the Banana Pi only works with DVI using very, very short cables. The Orange Pi is the only other one I have that is HDMI only. I hooked it up to my LCD TV just to make sure it works and haven't done anything with it since for obvious reasons. If I had known I probably wouldn't have bought it. Well, at least it was cheap and now I have a monitor "For HDMI - DVI , I think @@jas-mx can explain this better (would you, @@jas-mx?)." After almost three days of waiting the answer is apparently not. Given that the TDA19988 supports both I'd be more inclined to accept this if there was at least some attempt at a reasonable explanation (ping @@jas-mx?).
This has already being explained in the last post in this thread , unfortunately not many are willing to search before asking. If its not clear then read up on HDMI CEA and DMT modes. There is nothing stopping you attempting to code a kernel driver to do you what to require unfortunately not many have the experience or willingness to do so. I'd also point out I'm not part of the official UDOO team and therefore I'm not expected to answer within any time frame !
Yes I can see why having to point out which thread it was "explained" on was so difficult that it took three days to do it (official or not) ! Actually I did search and since DVI (a very important part of the search) does not appear anywhere in the thread you point to I'm fairly certain that is why it did not show up. As to the thread, it says nothing about DVI vs HDMI, it only talks about resolutions. To repeat my first post which you apparently did not read, the data sheet for the external HDMI controller also supports DVI 1.0, defaults to DVI, and must be programmed to use HDMI. I'm certain that it does not require a completely different kernel driver just to handle the chip being programmed differently or handling different resolutions for that matter since everybody else does it. Being or not being an official part of the team does not have much to do with a reasonably response time, and the response does not in any way answer or even attempt to answer the question. Andrea, Surely you guys can do better than this. Could I get an "official" response instead of some half a** attempt at deflection? I like the neo but I'm starting to really regret helping sponsor the project.
As I mentioned in my last post, if want to try to support DVI then you can try amending the kernel driver to do so. The reason I'm telling you this is because I wrote the current driver that is used by the NEO, after spending countless hours working out how the controller works (there is no public FULL datasheet available, what you have is a Short datasheet). What I'm failing to understand is this quote: To repeat my first post which you apparently did not read, the data sheet for the external HDMI controller also supports DVI 1.0, defaults to DVI, and must be programmed to use HDMI. I'm certain that it does not require a completely different kernel driver just to handle the chip being programmed differently or handling different resolutions for that matter since everybody else does it. I'm happy for you to patch the driver (or implement your own) as you wish, unfortunately as you haven't taken the time to understand what is involved when your making unfounded claims and not appreciating the work that has been done!
Dear @jas-mx, thanks for the answer. As Jas said, he's not part of the UDOO Team. He helps us a lot, but since he's not part of the team he's not requested to answer within a certain time frame. I asked him since he's surely way, way, way (can I say way one more time?) more competent than me, so I pinged him to ask to answer on my behalf as a favour. Regarding your problem, @Gary Stewart, I don't understand: you want us to write in the datasheet that DVI is not supported, do you? But in the datasheet you won't find DVI in "Video Out". What's the problem? Here's the datasheet: http://www.udoo.org/download/files/datasheets/datasheet_udoo_neo.pdf
There was no answer, just more deflection. I've already replied to the slow response. I already have the data sheet, it says in several places that it supports DVI 1.0, try search on the document. The BeagleBone Black uses the same chip and works with a DVI input monitor, I know, I have one. So tell me again why the neo can't. Really interesting product, too bad the only support available for a critical driver is "fix it yourself". Are there any others I should know about?
Hi Gary. Can you tell me where did you find in the UDOO datasheet that DVI is supported? The TDA1998, even if supports DVI, will not configure itself to generate a proper signal. jas-mx did a great job on the bootloader, kernel and device tree in order to support the HDMI, which is what is stated to be supported.
Hi Francesco, Section 2 Features and benefits * DVI 1.0 The best example is in section "7.14 E-EDID" specifically "7.14.2 HDMI and DVI" where it specifically states "However, even though the TDA19988 have directly access to that information, it is the task of the host processor to ask to switch from DVI to HDMI mode". This clearly states that no only is DVI supported, it is the default mode even after the E-EDID is read and in order to use HDMI it must be configured to do so by the processor it is connected to via the I2C interface. To be blunt, given the title of the section, I had no problem finding this using search on the data sheet and neither should anybody else. As I said in my previous response, the BeagleBone Black uses the same chip and I have had no problems using it with several DVI monitors I have so I know the TDA19988 works with them. I did not know it used the same chip until I got into this discussion and started searching the Internet for a better description of the configuration registers. This is one place where jas is absolutely correct, the lack of a registers description makes the data sheet useless from a driver programming perspective which is why searching the Internet for a better description, or even better any other code that might be available to configure it is the first thing I did. Although most of the code I found did not include a better register description it did not take long at all to come across the fact that the BB Black also uses the chip. I have not looked at the driver code myself but I would suggest that it might be a good starting point (I assume it is released under the GPL) to adding DVI and/or fixing other problems with the neo driver caused by a serious lack of data sheet information.
Hi Gary The TDA19988 chip supports DVI, but UDOO never stated that DVI is supported. jas-mx added support into the kernel for HDMI only. Since the driver is open source, it can be extended. Pull requests are welcome of course, since it is hard to expect the UDOO team can implement any request the users are asking on the forums in a short time frame. There is huge TODO list, and the UDOO team is way smaller than the Beagle team.
