[vbox-dev] Monitor count limitations

Rūdolfs Bundulis rudolfs.bundulis at gmail.com
Thu Sep 4 09:04:19 GMT 2014

> Good to know that it works!

Well, without the advices form you and Klaus I wouldn't have gone far, so
great thanks:) Btw, this is not that important, but since I plan to host
any OS with the wall, does OS X have any special tweaks like the windows
WDDM/XPDM that I should now about? So far I've checked Windows and XFCE and
they both worked fine, but Klaus arleady warned me that X11 is less
resource hungry than Windows. Does OS X fall into the same category as X11?

2014-09-04 11:49 GMT+03:00 Vitali Pelenjow <Vitali.Pelenjow at oracle.com>:

> Good to know that it works!
> Thanks,
> Vitali.
> Rūdolfs Bundulis wrote:
>> Hi Vitali,
>> no it does not. And I just found the issue, the H264 encoder was actually
>> stalling after the 1280x720 resize on all 25 monitors and since I was
>> checking this from home and I did not have access to the actual wall, I did
>> not see that. I fixed it an yeah, now I got all 25 to resize to full hd,
>> after they were all resized to 1280x720. So with XPDM the VRAM amount is
>> sufficient for my needs. Seems that I'll have to stack multiple GPU's or
>> combine GPU/CPU encdoing to actually be able to pull this amount of pixels
>> off at 25fps. Sorry for that, I hope I didn't take too much of your time
>> with the verifications done on your side  and thank you both (you and
>> Klaus) for the info - the XPDM thing was very important, now I can run all
>> the 5x5 wall with full hd.
>> Best Regards,
>> Rudolfs Bundulis
>> 2014-09-04 10:43 GMT+03:00 Vitali Pelenjow <Vitali.Pelenjow at oracle.com
>> <mailto:Vitali.Pelenjow at oracle.com>>:
>>     Does the VM have 2d acceleration enabled (in the VM settings)?
>>     Which version of VBox/guest addidions do you use?
>>     Please also send me VBox.log of the VM with 25 monitors.
>>     And the VM xml config file (VMNAME.vbox).
>>     I tried with current VBox trunk. Used one of existing Win7 32 bit
>>     VMs with XPDM driver.
>>     I edited the .vbox xml config to set 256MB VRAM and 24 monitors.
>>     Then started the VM with VBoxHeadless and on the host executed
>>     a batch script with VBoxManage controlvm setvideomodehint for each
>>     monitor.
>>     Then connected to the VMs first monitor with a RDP client and
>>     checked that
>>     Display Properties in the guest show all 24 monitors at 1920x1200.
>>     Vitali
>>     Rūdolfs Bundulis wrote:
>>         >I wonder why monitors in your guest resize to 1280x720.
>>         >Did you allow all modes in IFramebuffer::VideoModeSupported?
>>         >Can you run 1 monitor at 1920x1200?
>>         >How do you resize the guest monitors: from the guest or using
>>         VBoxManage
>>         >controlvm setvideomodehint?
>>         And I try to force the desired resolution like this:
>>         for (unsigned short nMonitorIndex = 0; nMonitorIndex <
>>         m_nMonitorCount; ++nMonitorIndex)
>>         {
>>         // Set full hd for all the screens
>>         CHECK_HRESULT(m_pDisplay->SetVideoModeHint(nMonitorIndex,
>>         true, false, 0, 0, 1920, 1080, 32));
>>         }
>>         One monitor runs fine, 7 also work, I didn't have time now to
>>         find exact boundary but I will do it. Bascially in all the
>>         configuriation the VirtualBox logs shows the hint for
>>         1920x1080 but a bit later just resizes to 1280x720 and does
>>         not even try that. I'll mail you the source and logs directly,
>>         thanks for the help.
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