A query on frame buffers

Fri Jan 7 01:00:35 PST 2011

On Fre, 2011-01-07 at 02:42 +0000, Prasad Joshi wrote: 
> On Mon, Dec 27, 2010 at 3:30 PM, Konrad Rzeszutek Wilk
> <konrad.wilk at oracle.com> wrote:
> > On Tue, Dec 21, 2010 at 04:51:04AM +0000, Prasad Joshi wrote:
> >> Hello All,
> >>
> >> This is probably my first mail on this mailing list. I am working on a
> >> university project on Nvidia or any GPU Pass-through in KVM. I have a
> >
> > You picking the hard ones first, eh? I would suggest you do Intel
> > or ATI as they have actually posted patches for this.
> 
> Thanks a lot for your reply.
> 
> Yes indeed, I started with the ATI Radeon RV370 card. Passing the
> Nvidia card is the ultimate aim of the project.
> 
> >
> >> question related to framebuffer.
> >>
> >> I was reading few documents on XEN VGA pass-through, the document says
> >> the first step for pass-through is mapping the framebuffers in the VM
> >> at specific address, specifically speaking 0xA0000 till 0xC0000.
> >
> > I would suggest you look at the code - there have been some patches
> > posted by AMD engineers on xen-devel for this.
> >
> 
> Yes I am looking at those patches as well, including some research
> papers on the same topic.
> 
> Here is what I have tried so far.
> I have 2 graphics cards connected to my machine
> 1. Nvidia: This is being used by host machine.
> 2. ATI: Want to pass-through this card to the VM.
> 
> I tried to pass-through the ATI card to VM. First, there was a problem
> with ROM BIOS. Then I passed a correct ROM BIOS to QEMU-KVM. Now when
> I start the VM with ATI card in pass-through mode.
> 
> I see some garbage output on the monitor attached to the ATI card. I
> also saw following messages in the system log.
> 
> [    2.162294] [drm] Initialized drm 1.1.0 20060810
> [    2.459594] [drm] radeon defaulting to kernel modesetting.
> [    2.459596] [drm] radeon kernel modesetting enabled.
> [    2.766698] radeon 0000:00:04.0: PCI INT A -> Link[LNKD] -> GSI 10
> (level, high) -> IRQ 10
> [    2.766734] radeon 0000:00:04.0: setting latency timer to 64
> [    2.783512] [drm] initializing kernel modesetting (RV380 0x1002:0x5B64).
> [    2.792407] [drm] register mmio base: 0x40000000
> [    2.792408] [drm] register mmio size: 65536
> [    2.797177] [drm] Generation 2 PCI interface, using max accessible memory
> [    2.797275] radeon 0000:00:04.0: VRAM: 128M 0x00000000F8000000 -
> 0x00000000FFFFFFFF (128M used)
> [    2.797284] radeon 0000:00:04.0: GTT: 512M 0x00000000D8000000 -
> 0x00000000F7FFFFFF
> [    2.798370] radeon 0000:00:04.0: irq 40 for MSI/MSI-X
> [    2.870703] radeon 0000:00:04.0: radeon: using MSI.
> [    3.151162] [drm] radeon: irq initialized.
> [    3.151539] [drm] Detected VRAM RAM=128M, BAR=128M
> [    3.151541] [drm] RAM width 128bits DDR
> [    3.151610] [drm] radeon: 128M of VRAM memory ready
> [    3.151611] [drm] radeon: 512M of GTT memory ready.
> [    3.151627] [drm] GART: num cpu pages 131072, num gpu pages 131072
> [    3.152701] [drm] radeon: 1 quad pipes, 1 Z pipes initialized.
> [    3.544943] [drm] PCIE GART of 512M enabled (table at 0xF8040000).
> [    3.548479] radeon 0000:00:04.0: WB enabled
> [    3.549020] [drm] Loading R300 Microcode
> [    3.554278] [drm] radeon: ring at 0x00000000D8001000
> [    3.778476] [drm:r100_ring_test] *ERROR* radeon: ring test failed
> (sracth(0x15E4)=0xCAFEDEAD)
> [    3.781010] [drm:r100_cp_init] *ERROR* radeon: cp isn't working (-22).
> [    3.782542] radeon 0000:00:04.0: failled initializing CP (-22).
> [    3.784006] radeon 0000:00:04.0: Disabling GPU acceleration
> [    3.793709] [drm] radeon: cp finalized
> [    3.834875] radeon 0000:00:04.0: ffff8800320b4c00 unpin not necessary
> [    3.841759] [drm] Radeon Display Connectors
> [    3.841766] [drm] Connector 0:
> [    3.841771] [drm]   VGA
> [    3.841777] [drm]   DDC: 0x60 0x60 0x60 0x60 0x60 0x60 0x60 0x60
> [    3.841781] [drm]   Encoders:
> [    3.841785] [drm]     CRT1: INTERNAL_DAC1
> [    3.841788] [drm] Connector 1:
> [    3.841791] [drm]   DVI-I
> [    3.841794] [drm]   HPD1
> [    3.841799] [drm]   DDC: 0x64 0x64 0x64 0x64 0x64 0x64 0x64 0x64
> [    3.841803] [drm]   Encoders:
> [    3.841806] [drm]     CRT2: INTERNAL_DAC2
> [    3.841809] [drm]     DFP1: INTERNAL_TMDS1
> [    6.158753] [drm] fb mappable at 0xF8040000
> [    6.158756] [drm] vram apper at 0xF8000000
> [    6.158757] [drm] size 5242880
> [    6.158758] [drm] fb depth is 24
> [    6.158759] [drm]    pitch is 5120
> [   13.914196] fb0: radeondrmfb frame buffer device
> [   13.914198] drm: registered panic notifier
> [   13.914683] [drm] Initialized radeon 2.7.0 20080528 for
> 0000:00:04.0 on minor 0
> 
> The errors
> 
> [    3.778476] [drm:r100_ring_test] *ERROR* radeon: ring test failed
> (sracth(0x15E4)=0xCAFEDEAD)
> [    3.781010] [drm:r100_cp_init] *ERROR* radeon: cp isn't working (-22).
> [    3.782542] radeon 0000:00:04.0: failled initializing CP (-22).
> [    3.784006] radeon 0000:00:04.0: Disabling GPU acceleration
> 
> Seem to be disabling GPU functionality. For now, I am interested in
> Graphics functionality of the ATI card and not GPGPU functionality.
> 
> I will appreciate if you can help me with some information on solving
> this problem. Let me know if I should be asking this question on
> another forum. Please keep me in CC.

Looks like dri-devel material, added to CC.

As a first guess, maybe the system memory pages accessed by the GPU GART
aren't the same ones intended for this by the VM.

-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer