Re: Not enough bandwidth with Magewell XI100DUSB-HDMI

[Philipp Zabel <p.zabel@pengutronix.de>]

Hi,

On Mon, 2018-05-21 at 15:03 -0700, Curt Meyers wrote:
> On 05/16/2018 04:55 AM, Mathias Nyman wrote:
> > On 15.05.2018 12:22, Michael Tretter wrote:
> > > Hi Mathias,
> > > 
> > > On Tue, 10 Apr 2018 18:22:03 +0300, Mathias Nyman wrote:
> > > > On 09.04.2018 11:21, Michael Tretter wrote:
> > > > > On Tue, 20 Feb 2018 15:29:28 +0200, Mathias Nyman wrote:
> > > > > > On 16.02.2018 15:28, Michael Tretter wrote:
> > > > > > > On Mon, 29 Jan 2018 14:02:57 +0200, Mathias Nyman wrote:
> > > > > > > > On 19.01.2018 22:12, Philipp Zabel wrote:
> > > > > > > > > On Fri, Jan 19, 2018 at 2:10 PM, Michael Tretter
> > > > > > > > > <m.tretter@pengutronix.de> wrote:
> > > > > > > > > > I found the old thread and it sounds exactly like my issue. 
> > > > > > > > > > Different
> > > > > > > > > > camera, but same xHCI controller.
> > > > > > > > > 
> > > > > > > > > I have exactly the same issue with the xHCI controller of my 
> > > > > > > > > laptop and
> > > > > > > > > "Oculus Sensor" USB3 isochronous mostly-UVC cameras:
> > > > > > > > > 
> > > > > > > > > 00:14.0 USB controller: Intel Corporation Wildcat Point-LP USB 
> > > > > > > > > xHCI
> > > > > > > > > Controller (rev 03) (prog-if 30 [XHCI])
> > > > > > > > >         Subsystem: Lenovo Wildcat Point-LP USB xHCI Controller
> > > > > > > > >         Flags: bus master, medium devsel, latency 0, IRQ 44
> > > > > > > > >         Memory at f2220000 (64-bit, non-prefetchable) [size=64K]
> > > > > > > > >         Capabilities: [70] Power Management version 2
> > > > > > > > >         Capabilities: [80] MSI: Enable+ Count=1/8 Maskable- 64bit+
> > > > > > > > >         Kernel driver in use: xhci_hcd
> > > > > > > > >         Kernel modules: xhci_pci
> > > > > > > > > 
> > > > > > > > > T:  Bus=02 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#=  4 Spd=5000 MxCh= 0
> > > > > > > > > D:  Ver= 3.00 Cls=ef(misc ) Sub=02 Prot=01 MxPS= 9 #Cfgs=  1
> > > > > > > > > P:  Vendor=2833 ProdID=0211 Rev= 0.00
> > > > > > > > > S:  Manufacturer=Oculus VR
> > > > > > > > > S:  Product=Rift Sensor
> > > > > > > > > S:  SerialNumber=WMTD3034300BCT
> > > > > > > > > C:* #Ifs= 2 Cfg#= 1 Atr=80 MxPwr=800mA
> > > > > > > > > A:  FirstIf#= 0 IfCount= 2 Cls=ff(vend.) Sub=03 Prot=00
> > > > > > > > > I:* If#= 0 Alt= 0 #EPs= 1 Cls=ff(vend.) Sub=01 Prot=00 
> > > > > > > > > Driver=uvcvideo
> > > > > > > > > E:  Ad=83(I) Atr=03(Int.) MxPS=  32 Ivl=128ms
> > > > > > > > > I:* If#= 1 Alt= 0 #EPs= 0 Cls=ff(vend.) Sub=02 Prot=00 
> > > > > > > > > Driver=uvcvideo
> > > > > > > > > I:  If#= 1 Alt= 1 #EPs= 1 Cls=ff(vend.) Sub=02 Prot=00 
> > > > > > > > > Driver=uvcvideo
> > > > > > > > > E:  Ad=81(I) Atr=05(Isoc) MxPS=1024 Ivl=125us
> > > > > > > > > I:  If#= 1 Alt= 2 #EPs= 1 Cls=ff(vend.) Sub=02 Prot=00 
> > > > > > > > > Driver=uvcvideo
> > > > > > > > > E:  Ad=81(I) Atr=05(Isoc) MxPS=1024 Ivl=125us
> > > > > > > > > 
> > > > > > > > > Any USB2 or USB3 device that I plug in while the first camera 
> > > > > > > > > is streaming in
> > > > > > > > > altsetting 1 or 2 causes the bandwidth error. The same happens 
> > > > > > > > > when I try to
> > > > > > > > > change the altsetting on an isochronous endpoint of an already 
> > > > > > > > > plugged device.
> > > > > > > > > While the camera is in altsetting 0, other devices can be 
> > > > > > > > > probed and work.
> > > > > > > > > > For some tests, I changed the xhci_change_max_exit_latency() 
> > > > > > > > > > function
> > > > > > > > > > to ignore the requested MEL and set the MEL to 0. Now the USB 
> > > > > > > > > > devices
> > > > > > > > > > are detected correctly.
> > > > > > > > > 
> > > > > > > > > Exactly the same thing helps here, as well. With this hack, 
> > > > > > > > > streaming from two
> > > > > > > > > of those cameras at the same time works without any apparent 
> > > > > > > > > problem:
> > > > > > > > > 
> > > > > > > > > ----------8<----------
> > > > > > > > > diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> > > > > > > > > index 297536c9fd00..3cb4a60d8822 100644
> > > > > > > > > --- a/drivers/usb/host/xhci.c
> > > > > > > > > +++ b/drivers/usb/host/xhci.c
> > > > > > > > > @@ -4025,7 +4025,7 @@ static int __maybe_unused
> > > > > > > > > xhci_change_max_exit_latency(struct xhci_hcd *xhci,
> > > > > > > > >             ctrl_ctx->add_flags |= cpu_to_le32(SLOT_FLAG);
> > > > > > > > >             slot_ctx = xhci_get_slot_ctx(xhci, command->in_ctx);
> > > > > > > > >             slot_ctx->dev_info2 &= cpu_to_le32(~((u32) MAX_EXIT));
> > > > > > > > > -       slot_ctx->dev_info2 |= cpu_to_le32(max_exit_latency);
> > > > > > > > > +       slot_ctx->dev_info2 |= cpu_to_le32(0);
> > > > > > > > >             slot_ctx->dev_state = 0;
> > > > > > > > > 
> > > > > > > > >             xhci_dbg_trace(xhci, trace_xhci_dbg_context_change,
> > > > > > > > > ---------->8----------
> > > > > > > > 
> > > > > > > > Ok, back after a week on sickleave.
> > > > > > > > I'm getting the magewell capture device and try to reproduce 
> > > > > > > > this myself.
> > > > > > > 
> > > > > > > I don't think that the issue is specific to the magewell capture
> > > > > > > device, but rather should be reproducible with any USB3 device with
> > > > > > > isochronous endpoints.
> > > > > > > 
> > > > > > > Anyway, please tell me, if I can somehow help you to get this 
> > > > > > > properly
> > > > > > > fixed.
> > > > > > 
> > > > > > I'm currently looking at device reset issues after suspend, but 
> > > > > > this is on the
> > > > > > todo list.
> > > > > > 
> > > > > > I got a magewell device, (haven't unboxed it yet)
> > > > > > Maybe step by step instructions to reproduce it could speed things 
> > > > > > up.
> > > > > 
> > > > > Did you have time to unbox and test the Magewell device?
> > > > 
> > > > This seems to always get postponed due to other work,
> > > > 
> > > > I just tried it out once today on a nearby laptop, gst-launch seems 
> > > > to work
> > > > but couldn't reproduce the bandwidth issue when connecting a second 
> > > > usb device.
> > > > 
> > > > But I haven't really tested it out properly yet.
> > > 
> > > I just tested with 4.17-rc5 and the behavior remains the same. Is there
> > > anything else I could do to get this fixed?
> > > 
> > 
> > Briefed Zhengjun about this issue, one more brain on it.
> > Adding him to the thread.
> > 
> 
> Isochronous has been a problem for me for 2 years. I am using a rare 3D 
> stereo camera from Etron and had Isochronous problems and recently I 
> have discovered that the Logitech Brio also has what appears to be the 
> same issue. The Logitech Brio is the first Logitech USB3 camera that 
> uses Isochronous mode and you can do a search and find that linux users 
> are having problems with it.

The Oculus Sensor devices contain Etron controllers as well (eSP770).

> My suggestion would be for the USB3 team to order several Logitech Brio 
> cameras and debug the Isochronous problems. My company paid for someone 
> to try and debug the problem and we came up with a patch that we sent to 
> Mathias but it was not accepted because the change was not well 
> understood. I can probably buy cameras for Mathias if he is interested, 
> you only need 2 to get started, would like to see 5 or more running 
> simultaneously.
> 
> The people at Etron also discovered that if you plug Isochronous cameras 
> into a hub with a Genesys Logic - GL3520 controller then it for some 
> reason masks the problem and allows multiple cameras to work. 
> Unfortunately this USB hub is extremely rare and I only found it in this 
> StarTech ST7300USBME hub. Also it doesn't work flawlessly but I have 
> tested it with 5 cameras.
> 
> My all Intel motherboard and chipset machines work perfect with MS 
> Windows but not with Linux so it is hard to blame the hardware.

Does anybody have new information about this issue? I tested last week
on v5.2-rc5, and the issue still persists unchanged (and forcing MEL=0
still helps).

regards
Philipp