Re: Xen VGA Passthrough - GTX 680 successfully hard-moded to GRID K2

[Gordan Bobic <gordan@bobich.net>]

 On Tue, 24 Sep 2013 20:46:52 +0100 (BST), David TECHER 
 <davidtecher@yahoo.fr> wrote:

> - VM = Win XP 64: if I set RAM > 3GB then the VM get slower. VM gets
> slower once NVIDIA driver is installed and that I restarted thsi VM
> :(. I tried a couple of things but unfortunately I was not to fix it.

 That is really weird - I haven't observed any obvious slowdown
 related to memory amount in XP64.

> Setting RAM  DVI-I Connector
> ----------------------------------------
> The dom0 has just started. There are two VMs (one XP 64 and one Win 7
> 64)
>
> Start XP 64...OK--> Screen works!
> Stop XP 64...OK--> Screen works!
> Start XP 64...OK--> Screen works!
> Restart XP 64...OK--> Screen works!
> Stop XP 64...OK--> Screen works!
> Start Win7 64 ...OK--> Screen works!
> Stop Win 64...OK--> Screen works!
> Start XP 64...KO ---> Black screen!!!
> xl destroy for this VM. And VM Win 7 64 can start properly...Screen
> works
>
> Output B => DVI Connector
> -------------------------------------
> The dom0 has just started. There are two VMs (one XP 64 and one Win 7
> 64)
> Start XP 64...OK --> Screen works!
>
> Stop XP 64...OK--> Screen works!
> Start XP 64...OK--> Screen works!
> Restart XP 64...OK--> Screen works!
> Stop XP 64...OK--> Screen works!
> Start Win7 64 ...OK--> Screen works!
> Stop Win7 64...OK--> Screen works!
> Start XP 64...KO ---> Black screen!!!
> xl destroy for this VM. And Win 7 64 can start properly...Screen 
> works
>
> Output C ==> mini HDMI
>
> --------------------------------
> The dom0 has just started. There are two VMs (one XP 64 and one Win 7
> 64)
> Start XP 64...OK--> Screen works!
> Stop XP 64...OK--> Screen works!
> Start XP 64...OK--> Screen works!
> Restart XP 64...OK--> Screen works!
> Stop XP 64...OK--> Screen works!
> Start Win7 64 ...OK--> Screen works!
> Stop Win7 64...OK--> Screen works!
> Start XP 64...KO --> Black Screen.
> xl destroy for this VM. And Win 7 64 can start properly...Screen 
> works
>
> Conclusion: whatever the connector is it seems doable to restart XP 
> 64
> ( no switch to Win 7 64!)

 This is presumably with the GTX680?
 So it seems to not work is booting XP64 AFTER using Win7.

 What I was asking was a little different, though, and
 specific to using dual-link DVI vs. single-link. You do,
 however, seem to be able to use display-port, which
 answers a part of my question, since that doesn't work
 for me at all.

 Let me recap the problem. I only get this on the GTX680
 (Quadrified to K5000 or Gridified to K2, happens in both
 cases) in domU. It does NOT happen with a GTX470/480 modified
 to Q5000/Q6000. On bare metal the modified GTX680 works fine,
 the issue does not arise. I only tried this on XP64, not
 attempted on Win7.

 Setup:
 - Xen 4.3.0
 - XP64 domU
 - GTX680 modified to K5000

 Symptoms:
 1) Using a VGA monitor works fine.
 2) Using a single-link DVI monitor works fine.
 3) Using a monitor capable of dual-link DVI modes but in low
 resolution where the card negotiates only a SL-DVI mode
 (<= 1280x800 on my Dell 3007WFP) works fine.
 4) Using a DL-DVI monitor with high resolution modes
 requiring DL-DVI link results in a blank screen (monitor goes
 to sleep immediately)
 5) DisplayPort use with active DL-DVI adapter results in
 monitor going to sleep in ANY mode (low or high res).

 In all cases the monitor is identified correctly and it's
 specific modes are listed.

 So to re-iterate the question - do you have a DL-DVI
 monitor you can try connecting to your GTX680 and see
 if DL modes work from domU XP64? Note: 1920x1200@60Hz
 is achievable using SL-DVI with reduced blanking so not
 all monitors that do 1920x1200 are necessarily DL-DVI.
 You can check this by looking at the Xorg log file if you
 are using the monitor on Linux, it should tell you what
 bandwidth is used for the mode. If if it is over 165MHz,
 it MUST be DL, if it is below, it may well be SL.

> For GTX480/Quadro 6000
> ====================
>
> The latest VMs I set up were a VM Win 7 64 and a VM Win XP 64. ( = 2
> VMs)
>
> - gfx_passthru=0 while setting up the VM -- before installing NVIDIA
> drivers. While VMs were setting up I used (native) VNC connection.
> (vnc=1)
>
> - gfx_passthru=1 once NVIDIA driver was installed.
>
> No patch was used!

 Hang on - are you saying that once the Nvidia driver is installed
 you can use gfx_passthry=1 an you get the SeaBIOS output and the
 boot-up Windows animaption on the domU monitor, rather than on
 the VNC console? Is your passthrough GPU the primary in dom0?

 Also note that if you have modified the GTX680 to a Grid K2 (well,
 half of a Grid K2), you can actually soft-mod it using a similar
 method to the Fermi (4xx series) cards to K5000 (not that there
 is much point, mind you). You just have to modify both the
 UEFI straps in the UEFI header and the BIOS straps in the normal
 BIOS wrapped into all that UEFI garbage (UEFI header is 1024 bytes,
 or 0x400 bytes in hex). Or you could just strip out the first 0x400
 bytes from the BIOS and all the trailing UEFI garbage after a
 little under 64KB - you can tell where the trailing padding starts
 by the fact it's all 0xFF filled). At the very bottom are the UEFI
 crypto certs which can also be removed.

 But if you have gfx_passthrough=1 working without side-loading
 the BIOS with the 64KB limitation, there is probably no point in
 doing this.

 Gordan