Boot screen on 4K display over DisplayPort?

Discussion in 'Mac Pro' started by antonio99, Feb 2, 2017.

  1. antonio99 macrumors member

    Feb 2, 2017

    I have a cMP with a GT120.

    I know the GT120 does not support 4K but I'd assume it should negotiate a lower resolution.

    When I connect it to a 4K monitor (Dell P2415Q) using the DisplayPort output I never see the boot screen.
    At some point a small progress bar appears on the lower left of the screen and then I get the login screen.

    When I connect it using the DVI output (using a DVI->HDMI cable, because the monitor only has DisplayPort and HDMI inputs) I can see the boot screen, but up to a point, then the screen is black.

    Anyway, that's for the GT120 and my current issues.
    I'm researching for a new card, but it is not easy to know if the boot screen will show up.
    There are threads saying that you need to be in 30Hz mode, others saying that only specific cards do that, etc.

    It appears that not all graphics cards can properly negotiate a working resolution when connected to a 4K screen during boot up, even if flashed.
    Is that correct?

    Is that an OSX bug?

    I would have thought they could start up in 1080p for example, and then switch to 4K, but it does not seems the case, right?

    Alternatively, which cards are supposed to show the boot screen at 4K over DisplayPort?

    Any advice will be highly appreciated.
  2. cdf macrumors 6502

    Jul 27, 2012
    To get a boot screen with the GT 120 over DisplayPort, you need to make sure that the monitor is set to DisplayPort 1.1 (the default setting is probably 1.2). Several flashed cards (such as the popular GTX 680) will display a 4k boot screen, albeit at 30 Hz. As far as I know, only flashed Maxwell cards (such as the GTX 750 Ti flashed by MacVidCards) can display a 4k boot screen at 60 Hz.
  3. antonio99 thread starter macrumors member

    Feb 2, 2017
    Thanks cdf.
    I checked and the monitor does not has a menu option to select DP 1.1 or 1.2 :-(

    Actually, I don't really need a boot screen at 4K60, it can be 4K30 or even 1080p, provided that:
    1) I see the boot screen somehow
    2) Once logged in OSX it runs at 4K60

    Does that sound reasonable? Would a flashed GTX680 do that?
  4. carpsafari Suspended


    Sep 13, 2015
    the Netherlands

    Horse crap.
  5. antonio99 thread starter macrumors member

    Feb 2, 2017
    Could you develop a little bit further your thoughts please? :)
  6. carpsafari Suspended


    Sep 13, 2015
    the Netherlands
    You want me to do your homework?
    Or make a full list of monitors capable to boot 4K?
  7. Fl0r!an, Feb 2, 2017
    Last edited: Feb 2, 2017

    Fl0r!an macrumors 6502a

    Aug 14, 2007
    All official Mac EFIs up to GTX 680 Mac Edition and HD 7950 Mac Edition don't support DP1.2, so you won't see a boot screen with any DP1.2 monitor connected (regardless of the actual resolution). You'd need to connect the display through HDMI or switch the monitor to DP1.1 mode (if possible).

    Only MVC's Maxwell cards support DP1.2 at EFI level. There are some rare exceptional cases where it seems to works with other cards, but that's nothing I'd rely on.
  8. antonio99 thread starter macrumors member

    Feb 2, 2017
    I don't need a list of monitors since I don't expect to change mine (*)
    However, I think understanding why there's a need for a specific monitor would probably be useful for everybody reading.

    I mean, WTF is wrong with the boot sequence to require a specific monitor, graphics card and cable combination (and why not, some specific coloured keyboard and ambient temperature... :))

    Forgive my naivety, but I would have thought that the only limitation to boot screen was the EFI on the graphics card that make it not recognised by the boot loader.

    Now, if that is incorrect, I would like to understand what other limitations/constraints there are, and why can't the boot sequence start with whatever graphics mode it can successfully negotiate with the monitor, and then later change if a better graphics driver is loaded.

    I mean, would expecting boot screen at 1080p, and then have the login screen at 4K, be like some unreasonable expectation from me?

    (*): As a side note, having a list of at least known to work monitors, just as those other threads about "list of compatible CPUs", "list of compatible graphics cards", etc. would probably help lots of people looking to buy a 4K monitor
    --- Post Merged, Feb 2, 2017 ---
    Does anybody knows the technical explanation behind that?
    Is it a bug? Is the bug on the MacPro firmware? Or in the graphics card firmware?
    Because it is strange that a digital protocol like DP (which I'm sure supports discovery and mode negotiation) cannot handle this situation.
    I mean, I would expect the monitor to say:
    "hey, I can do up to 1440p over DP1.1, and 4K over DP1.2"
    and then have the graphics card driver pick what it can do. The boot loader's graphics driver could pick DP1.1 and the OS could later switch to DP1.2.

    Thanks for the link. Seems pretty weird. Didn't now that a TM backup would restore NVRAM.

    Any European MVC resellers?
    Because the import taxes are expensive, and there should not be a need to pay them twice (card goes to MVC -import tax paid-, card goes to MVC's EU customer -import tax paid-), while a MVC reseller that flashed in Europe would have just one import tax, when the card entered EU.
  9. Fl0r!an macrumors 6502a

    Aug 14, 2007
    I guess it's a combination of both. The Mac Pro firmware most likely queries all possible display modes and blindly chooses the native one. That's not an unreasonable choice if you think about the time when the cMP's where made: Screens maxed out at 1440p, DP1.2 wasn't invented yet -> no reason to choose something lower than native res, no one wants to see a pixelated Apple logo at boot time. They just didn't think about GPUs which don't support native res during EFI stage.

    And yes, MVC has an official reseller in the UK.
  10. antonio99 thread starter macrumors member

    Feb 2, 2017
    So what makes some cards support native resolution at EFI stage?

    Note that I have issues with a GT120, official from Apple. Since that card does not support 4K nor DP1.2, it is strange that it fails to properly negotiate a lower resolution, it like there was no negotiation whatsoever.

    Your hypothesis about some bug in the GT120's firmware because it predates 4K and DP1.2 holds, I'm just wondering why a card that does support DP1.2 and 4K (like the GTX680 for example) would still fail the negotiation.

    Since other cards work (Maxwell flashed cards as you said), then it seems unlikely the issue could come from the Mac Pro firmware or the boot loader.

    Maybe the cards are improperly reporting supported video modes during EFI stage, right?
    Has anybody here investigated these issues, maybe checking what is the firmware doing, or comparing firmware versions?

    It this issue specific to DisplayPort?

    Thanks, though I did not find it in MVC's website.
  11. h9826790 macrumors G5


    Apr 3, 2014
    Hong Kong
    I think the only guy know the answer is MVC. And that's why he can develope the EFI by himself and make the Maxwell card able to show boot screen at 4K 60Hz.

    If you interested in it, you can also try to reverse engineer the EFI and find out what's happening.
  12. Fl0r!an macrumors 6502a

    Aug 14, 2007
    I guess the Mac Pro firmware just queries the display's native resolution (via EDID) and requires the GPU to set this mode, no matter if it's able to do so or not.
    I don't know if the 7950 and 680 are able to display a DP1.2 bootscreen in a UEFI PC, never tried that. Maybe the cards are generally not able to do so (because of firmware limitations), or it's just limited to the Mac GPUs, don't know.

    Maxwell EFI GPUs are a different story since the EFI isn't base on any Apple EFI.
  13. antonio99 thread starter macrumors member

    Feb 2, 2017
    Would that mean that the MVC guy developed the EFI firmware fix by himself? i.e.: that he fixed the "4K boot screen" issue by himself, or support for 4K is a "feature" present only on Maxwell cards?

    I wouldn't know where to start, but would be glad to take a look if I can get some pointers, any advice?

    By the way, I tried to register to the netkas forum, but I don't think that is working, I never get the email to activate the account.
  14. DPUser macrumors 6502a

    Jan 17, 2012
    Mind if I ask why you need the initial boot screen? Dual Boot? File Vault?
  15. carpsafari Suspended


    Sep 13, 2015
    the Netherlands
    You really do not need the 'bootscreen', but you konow Monkey see, monkey do.
    Its THE most overrated 'tip' to have your GPU flashed.
  16. antonio99 thread starter macrumors member

    Feb 2, 2017
    Actually a friend of mine came to me with the problem I stated.
    I don't know why he needs the bootscreen, probably multiboot, why?

    Whether it is because lack of interest or other reasons, I find strange that this question hasn't got its own sticky post, considering that 4K screens should probably be standard by now given the prices and advantages.
  17. netkas macrumors 65816

    Oct 2, 2007
    I think it is macstoreuk[dot]com

Share This Page

16 February 2, 2017