Where's my video card (Command line)?

This will be a quick article, I promise!

Here's is something that started when I was building a new VM. I wanted this VM in question to, as you probably have guessed, be able to access the video card using PCI passthrough. But I think some of you can find more interesting applications for this.

Since I cannot use the real machine, let's use a surrogate: an ASRock Z77 Extreme4-based computer (ok, I booted it off a liveCD; deal with it) which should has a Xeon E3-1200 onboard video.

Out good old friend lspci tells us that (I just grabbed the line that matched the name of the video controlelr)

00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09)

Can lspci provide us with more details? It actually can if we use option -s. Let's see what the man page tells us:

-s [[[[<domain>]:]<bus>]:][<slot>][.[<func>]]
              Show  only devices in the specified domain (in case your machine
              has several host bridges, they can either  share  a  common  bus
              number  space  or  each  of them can address a PCI domain of its
              own; domains are numbered from 0 to ffff), bus (0 to  ff),  slot
              (0  to  1f) and function (0 to 7).  Each component of the device
              address can be omitted or set to "*", both meaning "any  value".
              All  numbers  are  hexadecimal.  E.g., "0:" means all devices on
              bus 0, "0" means all functions of device 0  on  any  bus,  "0.3"
              selects  third  function of device 0 on all buses and ".4" shows
              only the fourth function of each device.

So, 00:02.0 means:

• 00 - Bus 0
  
• 02 - Slot 2
  
• 0 - All functions. Are there other functions I can see? I have not found, but that could be only for this guy

Then we rerun lspci with the above arguments:

[user@desktop ~]$ lspci -s 00:02.0 -v
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09) (prog-if 00 [VGA controller])
        Subsystem: ASRock Incorporation Motherboard
        Flags: bus master, fast devsel, latency 0, IRQ 29
        Memory at f7400000 (64-bit, non-prefetchable) [size=4M]
        Memory at e0000000 (64-bit, prefetchable) [size=256M]
        I/O ports at f000 [size=64]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: <access denied>
        Kernel driver in use: i915
        Kernel modules: i915


[user@desktop ~]$ 

How about cranking up the verbose mode while we are at it?

[user@desktop ~]$ lspci -s 00:02.0 -vvv
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09) (prog-if 00 [VGA controller])
        Subsystem: ASRock Incorporation Motherboard
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0
        Interrupt: pin A routed to IRQ 29
        Region 0: Memory at f7400000 (64-bit, non-prefetchable) [size=4M]
        Region 2: Memory at e0000000 (64-bit, prefetchable) [size=256M]
        Region 4: I/O ports at f000 [size=64]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: <access denied>
        Kernel driver in use: i915
        Kernel modules: i915

[user@desktop ~]$

I feel like I am being denied some info. Time to become root and shout at it surrender your secrets to me!

[root@desktop ~]# lspci -s 00:02.0 -vvv
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09) (prog-if 00 [VGA controller])
        Subsystem: ASRock Incorporation Motherboard
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0
        Interrupt: pin A routed to IRQ 29
        Region 0: Memory at f7400000 (64-bit, non-prefetchable) [size=4M]
        Region 2: Memory at e0000000 (64-bit, prefetchable) [size=256M]
        Region 4: I/O ports at f000 [size=64]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
                Address: fee0f00c  Data: 4191
        Capabilities: [d0] Power Management version 2
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [a4] PCI Advanced Features
                AFCap: TP+ FLR+
                AFCtrl: FLR-
                AFStatus: TP-
        Kernel driver in use: i915
        Kernel modules: i915

You have new mail in /var/spool/mail/root
[root@desktop ~]#

Now we get some more interesting info (look at the Control and Status lines).