Re: ehci-pci : WARNING: CPU: 0 PID: 347 at kernel/dma/direct.c:34

[John Donnelly <john.p.donnelly@oracle.com>]

> On Mar 31, 2020, at 9:17 AM, Alan Stern <stern@rowland.harvard.edu> wrote:
> 
> On Mon, 30 Mar 2020, John Donnelly wrote:
> 
>> The debug method produces the following:
>> 
>> iommu=on  ( no BCM is discovered )
>> 
>> [    9.911027] hub 4-0:1.0: state 7 ports 6 chg 0000 evt 0000
>> [    9.923028] usb 3-3: new high-speed USB device number 2 using xhci_hcd
>> [    9.950106] In hub_port_connect .. init
>> [    9.963879] usb 3-3: udev 2, busnum 3, minor = 257
>> [    9.963882] usb 3-3: New USB device found, idVendor=0424, 
>> idProduct=2660, bcdDevice= 8.01
>> [    9.978980] usb 3-3: New USB device strings: Mfr=0, Product=0, 
>> SerialNumber=0
>> [    9.994524] usb 3-3: usb_probe_device
>> [    9.994527] usb 3-3: configuration #1 chosen from 1 choice
>> [    9.994790] usb 3-3: adding 3-3:1.0 (config #1, interface 0)
>> [    9.994826] hub 3-3:1.0: usb_probe_interface
>> [    9.994828] hub 3-3:1.0: usb_probe_interface - got id
>> [    9.994831] hub 3-3:1.0: USB hub found
>> [   10.008224] hub 3-3:1.0: 2 ports detected
>> [   10.021669] hub 3-3:1.0: compound device; port removable status: FR
>> [   10.021671] hub 3-3:1.0: individual port power switching
>> [   10.021672] hub 3-3:1.0: individual port over-current protection
>> [   10.021674] hub 3-3:1.0: Single TT
>> [   10.021676] hub 3-3:1.0: TT requires at most 8 FS bit times (666 ns)
>> [   10.021678] hub 3-3:1.0: power on to power good time: 100ms
>> [   10.021753] hub 3-3:1.0: local power source is good
>> [   10.021872] hub 3-3:1.0: enabling power on all ports
>> [   10.022120] hub 2-1:1.0: state 7 ports 8 chg 0000 evt 0000
>> [   10.127115] hub 3-3:1.0: state 7 ports 2 chg 0000 evt 0000
>> [   10.327902] i8042: Can't read CTR while initializing i8042
>> 
>> 
>> Produces this configuration without the BCM devices :
>> 
>> 
>> lsusb -t
>> /:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
>> /:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 480M
>>     |__ Port 3: Dev 2, If 0, Class=Hub, Driver=hub/2p, 480M
>> /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
>>     |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M
>> /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
>>     |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
>> 
>> 
>> 
>> BCM is discovered  intel_iommu=off :
>> 
>> 
>> [    8.947539] usb 4-3: adding 4-3:1.0 (config #1, interface 0)
>> [    8.947569] hub 4-3:1.0: usb_probe_interface
>> [    8.947571] hub 4-3:1.0: usb_probe_interface - got id
>> [    8.947574] hub 4-3:1.0: USB hub found
>> [    8.960496] usb 3-1: skipped 1 descriptor after interface
>> [    8.960499] usb 3-1: skipped 1 descriptor after interface
>> [    8.960562] hub 4-3:1.0: 2 ports detected
>> [    8.974067] usb 3-1: default language 0x0409
>> [    8.974074] hub 4-3:1.0: compound device; port removable status: FR
>> [    8.974075] hub 4-3:1.0: individual port power switching
>> [    8.974077] hub 4-3:1.0: individual port over-current protection
>> [    8.974079] hub 4-3:1.0: Single TT
>> [    8.974081] hub 4-3:1.0: TT requires at most 8 FS bit times (666 ns)
>> [    8.974083] hub 4-3:1.0: power on to power good time: 100ms
>> [    8.974157] hub 4-3:1.0: local power source is good
>> [    8.974259] hub 4-3:1.0: enabling power on all ports
>> [    8.979469] usb 3-1: udev 2, busnum 3, minor = 257
>> [    8.979473] usb 3-1: New USB device found, idVendor=03f0, 
>> idProduct=7029, bcdDevice= 0.02
>> [    8.994797] usb 3-1: New USB device strings: Mfr=1, Product=2, 
>> SerialNumber=0
>> [    9.010633] usb 3-1: Product: Virtual Keyboard
>> [    9.024416] usb 3-1: Manufacturer: BMC
>> [    9.037858] usb 3-1: usb_probe_device
>> [    9.037860] usb 3-1: configuration #1 chosen from 1 choice
>> [    9.039418] usb 3-1: adding 3-1:1.0 (config #1, interface 0)
>> [    9.041507] usb 3-1: adding 3-1:1.1 (config #1, interface 1)
>> [    9.076272] hub 4-3:1.0: state 7 ports 2 chg 0000 evt 0000
>> 
>> I am not accustomed to looking the USB Bus.port.dev mappings , obviously 
>> with BCM discovered there are 05 Bus instead of 4 .
>> 
>> /:  Bus 05.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M
>> /:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 480M
>>     |__ Port 3: Dev 2, If 0, Class=Hub, Driver=hub/2p, 480M
>> /:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
>>     |__ Port 1: Dev 2, If 0, Class=Human Interface Device, 
>> Driver=usbhid, 12M
>>     |__ Port 1: Dev 2, If 1, Class=Human Interface Device, 
>> Driver=usbhid, 12M
>> /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
>>     |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M
>> /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/2p, 480M
>>     |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M
> 
> It seems pretty clear that your system (or at least the BMC part)  
> doesn't work as intended when the iommu is turned on.
> 
>> Here are the pci mappings:
>> 
>> [    6.381615] input: BMC Virtual Keyboard  as 
>> /devices/pci0000:00/0000:00:1c.2/0000:01:00.4/usb3/3-1/3-1:1.0/0003:03F0:7029.0001/input/input1
>> [    6.463638] hid-generic 0003:03F0:7029.0001: input,hidraw0: USB HID 
>> v1.01 Keyboard [BMC Virtual Keyboard ] on usb-0000:01:00.4-1/input0
>> [    6.496589] input: BMC Virtual Keyboard  as 
>> /devices/pci0000:00/0000:00:1c.2/0000:01:00.4/usb3/3-1/3-1:1.1/0003:03F0:7029.0002/input/input2
>> [    6.529449] hid-generic 0003:03F0:7029.0002: input,hidraw1: USB HID 
>> v1.01 Mouse [BMC Virtual Keyboard ] on usb-0000:01:00.4-1/input1
>> [    6.563139] usbcore: registered new interface driver usbhid
>> [    6.580222] usbhid: USB HID core driver
> 
> I don't know why you call these "pci mappings".  They have nothing to 
> do with PCI, and the last two lines don't talk about mappings at all.
> 
>> The last activity done seen on both traces is :
>> 
>>     "  enabling power on all ports  "
> 
> Why do you say this is the last activity seen on both traces?  In both
> of the log extracts you included above there are plenty of lines
> following those "enabling power" messages.
> 
>> Is this when the BCM discovery is suppose to  occur ? In the function 
>> example is when the udev appears:
>> 
>>    usb 3-1: udev 2, busnum 3, minor = 257
> 
> The BCM discovery is supposed to occur at the time you see it in the 
> second log extract above.
> 
> One thing I didn't notice before: With iommu=off, you get an entire new 
> USB host controller and bus.  It is called bus 3, and neither it nor 
> the 3-1 device (mouse and keyboard) is present when iommu=on.  In 
> fact, by comparing the listings you can see that buses 4 and 5 (with 
> iommu=off) are really the same as buses 3 and 4 (with iommu=on).
> 
> I'd say that your BMC does not work with iommu=on, and it is that
> failure which causes these extra devices not to be discovered.  In
> fact, they appear not be real physical devices at all, but rather
> virtual devices created by the BMC firmware.
> 
> If you want to find out why the BMC doesn't work with iommu=on, you 
> should ask the company that manufactured your computer's motherboard.  
> They are probably the only people who know the answer.
> 
> Alan Stern
> 


  Hi Alan.

Thank you for your assistance and insight.   I’ve tried  older kernels  (4.14, and 4.18 ) with iommu=on
and the BMC is recognized . This is obviously a regression somewhere  along the way.


Let me do some more bisecting.

Thank you,
JD