Boot screen on 4K display over DisplayPort?

[antonio99]

Hi,

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.

 

[cdf]

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.

 

[antonio99]

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?

 

[carpsafari]

.. 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.

********!

Horse crap.

 

[antonio99]

********!

Horse crap.

Could you develop a little bit further your thoughts please?

 

[carpsafari]

You want me to do your homework?
Or make a full list of monitors capable to boot 4K?

 

[Fl0r!an]

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.

 

[antonio99]

You want me to do your homework?
Or make a full list of monitors capable to boot 4K?

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
[doublepost=1486059726][/doublepost]

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).

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.

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

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.

 

[Fl0r!an]

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.

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.

 

[antonio99]

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.

Thanks.
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?

And yes, MVC has an official reseller in the UK.

Thanks, though I did not find it in MVC's website.

 

[h9826790]

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.

 

[Fl0r!an]

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.

 

[antonio99]

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.

Thanks.
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?

If you interested in it, you can also try to reverse engineer the EFI and find out what's happening.

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.

 

[DPUser]

Mind if I ask why you need the initial boot screen? Dual Boot? File Vault?

 

[carpsafari]

Mind if I ask why you need the initial boot screen? Dual Boot? File Vault?

You really do not need the 'bootscreen', but you konow Monkey see, monkey do.
Its THE most overrated 'tip' to have your GPU flashed.

 

[antonio99]

Mind if I ask why you need the initial boot screen? Dual Boot? File Vault?

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.

 

[netkas]

Thanks, though I did not find it in MVC's website.

I think it is macstoreuk[dot]com

 

[drolson]

got two GT120 Apple video cards i bought for the boot screen otherwise i use the GTX 7XX, 5XX, 6XX Nvidia Kepler cards in the 2008 Mac Pro 3,1 and the 2009-2012 Mac Pro 5,1, the GTX 760, 770, 780ti, 680, 670, 570, any of these work fine but no boot screen, can have the GT120 in the 2nd 16x slot at the same time for a boot screen and it boots on the card that is plugged into video, the GTX card that is not will boot next time when plugged in but has the Res. of the GT120 and has to be changed, or put the GT 120 in only when the boot screen is needed, works great but only one problem

i have two GT 120 Apple video cards, one is a 639-0376 and one is a 630-9643/T0034, they both work great with a monitor that is NOT! 4K, if the monitor is 4K the 639-0376 dose not work right with the sleep function, when it boots to the OS or goes to sleep it comes on and flashes the screen on and off till the sleep function is activated again then it stops, otherwise it works fine when the monitor is not 4K, with the GT 120 630-9643/T0034 the sleep function works great with either monitor 4K or non 4K, while testing both GT 120 Video cards it was booting to Mojave 10.14.6 on a Early 2008 Mac Pro 3,1 with the GT 120 DP port, then put back to a GTX 670 using 3840X2160 Res. on the HDMI port, the GT 120 is all done on the DP port, the DVI port will work but not the best

if getting a GT 120 Apple Video card for a boot screen get a 630-9643/T0034, why it works different than the 639-0376 i have yet to find out, been searching the internet, if somebody knows why these GT 120 models are different let me know