Mac Pro 5,1 and 4K Display Issues at Boot

[UKenGB]

I have since read a Mac EFI flashed GTX780 being described thus:-

"Apple Boot Screen Support for non 4K monitors (Mac EFI).
4K monitors won't show a boot screen through DisplayPort."

Which rather contradicts other statements to the contrary here and by MVC who I have contacted to confirm either way.

 

[bookemdano]

Yeah I lean towards MVC's statement being misleading (perhaps unintentionally). I think what he meant was that the Kepler cards will display bootscreens on monitors that have a native resolution up to 2560x1600. In addition they will work with 4K monitors via DisplayPort 1.2 once macOS has booted (which is to say they will not work with those monitors before booting). I think those are two different statements that were worded in such a way such that they could be misconstrued.

I think the hanging at boot issue though only occurs when you have a single 4K monitor connected via DP 1.2. So, what I think works (with both the 7950 and Kepler cards) is connecting a non-4K monitor to one of the card's other outputs so that boot screens show up on that monitor. You can keep your 4K monitor connected to the DP output in DP 1.2 mode and it will come to life after macOS boots. In the end I decided against that solution because I didn't have the desk space for two monitors and in general I'm not a fan of multi-monitor setups because I often lose track of where the pointer is. You could even buy one of those tiny 7" HDMI field monitors they make for DSLRs and connect that, though I would imagine you'd want to power it off after booting so you wouldn't have to deal with accidentally moving the mouse pointer over to it.

I will say that living with a 4K monitor on the cMP gets much better if you're willing to give up on bootscreens. With Mojave I was forced into that decision (no FileVault even if I did have an EFI Metal card, and no NVIDIA web drivers available for my MVC-flashed 750 Ti). Since the EFI driver is no longer involved I can boot just fine with my 4K DP1.2 monitor as the only connected display. But boy did I spend a lot of time researching other ways around this issue--and the truth is that they all suck.

Edit: When (if) you hear back from MVC please update the thread!

 

[UKenGB]

Yes I will do, but if this is the case, the GTX780 would provide no better solution than the HD7950 I'm using currently. Although I've not tested that the HD7950 can do 4K @ 60 Hz though, whereas the GTX780 can apparently do that.

Anyone confirm 4K @ 60Hz from the HD7950?

I should be able to test tomorrow assuming cable arrives, but would be good to know before if anyone can confirm.

 

[bookemdano]

Yes I will do, but if this is the case, the GTX780 would provide no better solution than the HD7950 I'm using currently. Although I've not tested that the HD7950 can do 4K @ 60 Hz though, whereas the GTX780 can apparently do that.

Anyone confirm 4K @ 60Hz from the HD7950?

I should be able to test tomorrow assuming cable arrives, but would be good to know before if anyone can confirm.

Yep the 7950 is perfectly capable of 4K @ 60Hz once macOS loads. I had it working just fine. You just have to make sure your 4K monitor is set to DisplayPort 1.2 mode and that you're using a DisplayPort cable to connect the card to your monitor (can't use HDMI, DVI or VGA).

Just keep in mind that if the card is flashed, you'll have to figure out a solution for booting (unplug the monitor until booted, use a secondary non-4K monitor on one of the other outputs, flip the BIOS switch to use the non-flashed ROM, etc.). But yeah, once you boot, the 7950 should give you no problems with 4K @ 60Hz over DP.

 

[UKenGB]

Yep the 7950 is perfectly capable of 4K @ 60Hz once macOS loads. I had it working just fine. You just have to make sure your 4K monitor is set to DisplayPort 1.2 mode and that you're using a DisplayPort cable to connect the card to your monitor (can't use HDMI, DVI or VGA).

Just keep in mind that if the card is flashed, you'll have to figure out a solution for booting (unplug the monitor until booted, use a secondary non-4K monitor on one of the other outputs, flip the BIOS switch to use the non-flashed ROM, etc.). But yeah, once you boot, the 7950 should give you no problems with 4K @ 60Hz over DP.

I have resigned myself to the fact that there is NO card that will provide boot/splash screen when connected solely to a 4K monitor via DP 1.2. I thought the GTX780 was the solution to that, but more recently have been disappointed to discover that is not true. Well, unless MVC can convince me otherwise and I'm still waiting to hear back from them.

I don't really want to keep another monitor around just for that as in any case I rarely have to re-boot, but I do want to be able to see those boot screens. So my best solution (until someone can suggest a better one) is to switch the monitor into DP 1.1 to boot, then switch it back to DP 1.2. Not a huge deal, but irritating all the same and I find it astonishing that this is the best that can be achieved with what was not too long ago Apple's premier Mac. Remember when Apple made sure the switch to Power Mac was done with full compatibility for 68K CPUs specifically to ensure the older machines could still run. Ha, long gone are the days when Apple cared so much about their customers.

 

[bookemdano]

I have resigned myself to the fact that there is NO card that will provide boot/splash screen when connected solely to a 4K monitor via DP 1.2. I thought the GTX780 was the solution to that, but more recently have been disappointed to discover that is not true. Well, unless MVC can convince me otherwise and I'm still waiting to hear back from them.

I don't really want to keep another monitor around just for that as in any case I rarely have to re-boot, but I do want to be able to see those boot screens. So my best solution (until someone can suggest a better one) is to switch the monitor into DP 1.1 to boot, then switch it back to DP 1.2. Not a huge deal, but irritating all the same and I find it astonishing that this is the best that can be achieved with what was not too long ago Apple's premier Mac. Remember when Apple made sure the switch to Power Mac was done with full compatibility for 68K CPUs specifically to ensure the older machines could still run. Ha, long gone are the days when Apple cared so much about their customers.

You can certainly do the DP1.1/1.2 switcharoo. How long you can keep doing it depends partially on how annoying it is to perform on your particular monitor. For me, it was damn near impossible (the monitor had to be receiving a signal in order to display the menu and it was buried like three levels deep. Oh and my monitor has those awful touch-sensitive "buttons". So I quickly ruled out that solution in my case.

I think something you need to seriously ask yourself is if you truly need to see bootscreens every time you boot. There are only two cases where I would think that's the case:

1. FileVault - That was my reason. But my choice to go to Mojave meant that I had to give up on using FV anyway.
2. Startup Manager aka Boot Picker aka Option booting - Where you constantly are switching back and forth between different macOS/OS X installs or between Mac and Windows and want the ability to choose your startup volume at every boot

If you don't regularly use either of those two things, then having boot screens at every boot isn't all that necessary. Even switching between Windows and macOS can be done natively from inside those two OSes now, so there isn't much reason left (on Mojave anyway) to need boot screens.

The nice thing about the 7950 is that it *can* do bootscreens when necessary. So in cases where you do need to option-boot or use verbose mode for example, all you'd have to do is flip the switch on the card over to the EFI BIOS. No need to physically swap out cards like many of the rest of us have to do.

 

[UKenGB]

You can certainly do the DP1.1/1.2 switcharoo. How long you can keep doing it depends partially on how annoying it is to perform on your particular monitor. For me, it was damn near impossible (the monitor had to be receiving a signal in order to display the menu and it was buried like three levels deep. Oh and my monitor has those awful touch-sensitive "buttons". So I quickly ruled out that solution in my case.

I think something you need to seriously ask yourself is if you truly need to see bootscreens every time you boot. There are only two cases where I would think that's the case:

1. FileVault - That was my reason. But my choice to go to Mojave meant that I had to give up on using FV anyway.
2. Startup Manager aka Boot Picker aka Option booting - Where you constantly are switching back and forth between different macOS/OS X installs or between Mac and Windows and want the ability to choose your startup volume at every boot

If you don't regularly use either of those two things, then having boot screens at every boot isn't all that necessary. Even switching between Windows and macOS can be done natively from inside those two OSes now, so there isn't much reason left (on Mojave anyway) to need boot screens.

The nice thing about the 7950 is that it *can* do bootscreens when necessary. So in cases where you do need to option-boot or use verbose mode for example, all you'd have to do is flip the switch on the card over to the EFI BIOS. No need to physically swap out cards like many of the rest of us have to do.

Well I'm certainly not thinking of crawling around under my desk, removing the side cover of my cMP and fumbling with a ridiculously small slide switch, then putting it all back together again every time I want to boot

I can access the monitors controls, so switching its options is not too hard to do. I'd prefer to not even have to do this, but as I said before, it really looks like there is NO card available that can provide everything we want, i.e. so a cMP behaves as a Mac should.

Something else has occurred to me though. What is it that prevents the booting as we're discussing. Is it DP 1.2 or is it the 60 Hz?

Currently the monitor is set to DP 1.2 and the Mac to 60 Hz and although I've not actually tested it yet, I am assuming it won't boot like that. But what if I simply use Sys Prefs/Displays to set it to 30 Hz. Would it then boot, or is it specifically DP 1.2 it can't handle?

 

[bookemdano]

Well I'm certainly not thinking of crawling around under my desk, removing the side cover of my cMP and fumbling with a ridiculously small slide switch, then putting it all back together again every time I want to boot

I can access the monitors controls, so switching its options is not too hard to do. I'd prefer to not even have to do this, but as I said before, it really looks like there is NO card available that can provide everything we want, i.e. so a cMP behaves as a Mac should.

Something else has occurred to me though. What is it that prevents the booting as we're discussing. Is it DP 1.2 or is it the 60 Hz?

Currently the monitor is set to DP 1.2 and the Mac to 60 Hz and although I've not actually tested it yet, I am assuming it won't boot like that. But what if I simply use Sys Prefs/Displays to set it to 30 Hz. Would it then boot, or is it specifically DP 1.2 it can't handle?

You still never answered why you require having bootscreens at every boot. I never suggested crawling under your desk every time you want to boot--only for the times when you absolutely need to see a boot screen, which for many of us (who don't use FV) is not terribly often at all.

And no, your idea of setting macOS to 30Hz will not work, because the EFI environment does not use those settings. It automatically tries to use the native resolution for the monitor/output combination, so in the case of DP connected to a 4K monitor at DP 1.2 it tries to display the boot screens at 4K @ 60Hz. No way to alter that choice (without perhaps modifying the EFI driver which is beyond the capabilities of 99.999999% of us).

 

[UKenGB]

You still never answered why you require having bootscreens at every boot. I never suggested crawling under your desk every time you want to boot--only for the times when you absolutely need to see a boot screen, which for many of us (who don't use FV) is not terribly often at all.

You're right, it's not often in any case, but I do want to see the boot screen and know I can select an alternative boot disk if I need to. Although I don't normally have major problems with this cMP, trying to get it running Mojave has been a nightmare, with corrupt bootrom that needed fixing (thanks @tsialex) and then a faulty HD7950 and also other odd issues I had with 10.14.0 that 10.14.1 seems to have fixed. With freezes that were able to corrupt the OS installation in some way that required a fresh install to fix, I really needed to see that boot screen. So while when everything's performing perfectly it's not strictly necessary, my recent experience means that more than ever, I do want to see it.

It may be that for a normal boot, I am happy to not see it, but I need to know I easily can.

And no, your idea of setting macOS to 30Hz will not work, because the EFI environment does not use those settings. It automatically tries to use the native resolution for the monitor/output combination, so in the case of DP connected to a 4K monitor at DP 1.2 it tries to display the boot screens at 4K @ 60Hz.

I thought that was probably the case, but thanks for confirming it.

No way to alter that choice (without perhaps modifying the EFI driver which is beyond the capabilities of 99.999999% of us).

Ah, if only. All we need is EFI that can actually display the boot screen under all conditions. For AMD and Nvidia cards. Such a small thing to ask.

Hang on though. it was said previously that the boot screen is not necessarily displayed in the native resolution, so presumably the problem is that the EFI is trying to use DP 1.2 and cannot, rather than the actual display parameters themselves being the problem?

Didn't I read earlier that MVC have prepared their own EFI? So it must be possible to produce a custom EFI that could display boot screen over DP 1.2. Way beyond me, but surely someone can. What a huge benefit that would be to so many of us.

 

[UKenGB]

Ok, here's how it is on my cMP 4,1=>5,1 with 10.14.1 and flashed HD7950 connected to LG 38WK95C-W (ultra wide) monitor set to DP 1.2 and displaying 3840x1600@60Hz.

It is my belief (correct me if I'm wrong) that the EFI displays the logo/splash/boot screen until the progress bar gets to about 2/3 and then the OS driver takes over, although continuing to display basically the same thing. This switch might be an almost unnoticeable flash of the screen (as on the original HD4870), or on the HD7950s I have tested, the screen goes black for a good 5 seconds. Bigger driver taking longer to load maybe? Anyway, this switchover point is relevant.

When booting and set to DP 1.2, the screen stays black for a while, but it continues to boot and then at that switch point when the driver loads, the display springs into life and the progress bar quickly goes away and I have the login screen.

This is rather better than for some who find that in this configuration, it simply won't boot. At least mine does continue even though I don't see the EFI boot screen.

If I switch the monitor to DP 1.1 (well the option is actually to disable DP 1.2 which basically means it is set to DP 1.1) either while logged in prior to restarting, or while the cMP is off, either way, using the monitor's built-in menu system, then the cMP boots correctly with full boot screen from Apple logo to the login screen. But...

The monitor's USB port turns ON/OFF in sync with the monitor's power state and if the keyboard is connected to the monitor's USB outlet (the monitor is connected to the cMP by its own USB cable, much like the ACD), during the restart process the monitor has time to go to sleep (i.e. low power mode) and turn off it's USB ports, so if trying to restart in recovery mode or anything else that requires keys pressed down on the keyboard, those keys will be missed. I tried several restarts into recovery mode which resulted in a normal boot to the login screen. I switched the keyboard to connect direct to the cMP's USB port and I was able to then boot into recovery mode. I need to check if I can delay the switching into low power mode by the monitor. Add another few seconds and this wouldn't be a problem. Not yet discovered how to do that though.

So not a major hurdle, but yet another gotcha that has to be overcome when dealing with these older Macs that Apple want us to junk and buy new replacements. However, despite that, this cMP and this monitor is an AWESOME combination. I am about to add a PCIe based NVMe boot disk and upgrade to dual x5690 CPUs so then it really will be maxed out. But, that should be more than enough for me for many years to come - as long as we can get around Apple's continued attempts to sideline these great machines.

 

[bookemdano]

Apologies if I missed that you were using an ultrawide in an earlier post. The problem this thread is about is connecting a 4K monitor to a flashed card in the cMP. It's been well-established that ultrawides don't have this problem. In fact, as I recall there were a few users who experienced this issue and "solved" it by returning their 4K monitor and buying an ultrawide instead.

Something about the combination of 2160 vertical resolution and DP 1.2 makes the EFI drivers freak out/not work. I don't know enough about EFI drivers to speculate as to why, but not much we can do about it.

 

[Riot Nrrrd]

Didn't I read earlier that MVC have prepared their own EFI? So it must be possible to produce a custom EFI that could display boot screen over DP 1.2. Way beyond me, but surely someone can. What a huge benefit that would be to so many of us.

Sorry to resurrect this necro post/thread but boy, how interesting is it to read this whole thread - and especially this paragraph - in early 2025, amidst these heady days of EnableGOP ... 🤯