I recently bought a HD7770 to go with my HD7870 so that I could VM windows in linux. I have a few problems and questions that I'm wondering if you guys can answer.
Posted below I have an image of what shows up on my screen when I boot into Fedora 20 upon installing a second graphics card. The DM seems to be working fine, but the WM seems to be messing up pretty badly (the picture has the settings menu "open"), also I don't have a mouse pointer but I can still select things. I'm assuming the solution to this problem has to deal with X, but since I can't open up any windows without them looking like that, I can't figure out how I'm supposed to set xconf to include two gfx cards. Will I have to do it all by command line (I mean not even booting into a DM, just straight CL) or is there some other issue here that I can't figure out?
That's really my only issue, its just that its a big one so its making this hard to get started. Now on to questions.
First, I haven't been able to find an answer as to whether or not I can bind linux to a pci-e slot that isn't the first in the board. I'm running an M5a97 R2.0 from Asus and the only pci-e lane that is x16 is the first one. I'd like for windows to be able to bind to that card (the HD7870) so it has full bandwidth, instead of the second. I haven't found a definitive article on binding pci-e lanes in linux so I don't know if this can be done. (I should note that I have found articles saying that kvm passthrough does indeed work with IOMMU on this board, so at least it wouldn't be doing this all for nought).
Second, If I bind linux to the second pci-e slot, will it stay bound, or will I have to rebind it every time I want to use the VM? It seems like when the system boots it automatically assumes the first card is what I want to use, and thus binds to that. I'm wondering if I can make the rebinding persistant across boots so I don't have to go through that all the time. I guess I could make a script if I have to, so that's not a big deal, this is more for curiousity's sake.
I think that's all for now. Those are my major issues so far. I hope I've given the necessary info. There are some "errors" I think when Fedora first boots but since I'm on an SSD they go by so fast I can't read them. I don't know the keywords that I should be searching for so I haven't found a way to pause or find those errors in logs for you guys. Maybe that would explain this stuff but I'm not sure.
So you're getting that screen when you install but not connect a second graphics card in the secondary slot?
Depending on your BIOS, you can define the order of the graphics cards. It is very important to have the host card running on KMS drivers and have it set as primary card at boot, otherwise you won't be able to unbind it very easily.
I get that type of screen only when I install the second card. If I boot with only the first card installed everything works just fine, that's why I was thinking maybe X isn't set up for two cards.
I'll dig into my Bios some more. I don't think there's an option to choose PCI-e order but we'll see. Maybe it's there somewhere. I'll get back to you on that.
Okay, so I checked my Bios. It looks like there isn't an option for choosing what PCI-e lane gets used, it just automatically uses the first one...unless I'm missing something buried deep in menus. It is an Asus board and I've heard plenty of stories of how their Bios suck when it comes to this type of thing.
How do you suggest I check x.conf? If I open terminal it does relatively the same graphical glitching as the settings menu does (all windows have that problem). Also I'm pretty sure its recognizing the cards attached. I can change the input of my monitor to the second input and it shows an extended desktop (when I switch back I either get a black screen or a rainbow of colors, so there's that as well). So its at least outputting through both cards. Should I unplug the second card and setup x.conf with a single card and then attach the second card and boot up to see if it works? Or should I be using both when I edit x.conf? Sorry for all the questions, I don't really understand how x works. I get that it interfaces with the drawing/creation of windows, but past that I don't really know what goes on.
Boot without x. That can be easily done by editing the boot parameters in grub or whatever boot manager you use. Just add 3 at the end of the line where the driver parameters are. Also delete "quiet" in that line so that you get full feedback on what the system does step by step when booting up.
You can run the cards in sli with proprietary drivers, but not with kms drivers. So it should be two separate adapters. This would be the default config the system would do. The glitching might be caused by wrong sync speeds after a bad identification by the monitor. That doesn't happen a lot, but it can happen. That can be solved with xrandr.
I don't have the sli bridge on the cards because I assumed that if I'm binding them to different OS's that I would need them separate. I'll try out the booting and see if I can fix it from there. I'll get back to you once I spend some time trying that stuff out.
