On Wed, 15 Oct 2014, Naveen Kumar Parna wrote:
> Hi Oliver,
>
> I tried this test in two different set of hardware configurations.
>
>
>
> i) I tried in multiple test systems which has
> EHCI-USB host controller on PCI card and internal USB 2.0
> hub("rate-matching" hub). All the test systems with this configuration
> gives spurious stall packets.
>
> [lowerlayers@banunxcas29 ~]$ lspci | grep -i usb
>
> 00:1a.0 USB Controller: Intel Corporation 5 Series/3400 Series Chipset
> USB2 Enhanced Host Controller (rev 05)
>
> 00:1d.0 USB Controller: Intel Corporation 5 Series/3400 Series Chipset
> USB2 Enhanced Host Controller (rev 05)
>
>
> lsusb:
>
> Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
>
> Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
>
> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>
> Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
>
>
>
>
>
> ii) I found different test systems which has
> OHCI-USB host controller on PCI card and internal USB 1.1 hub. All the
> test systems with this configuration are not producing stall packets.
>
> [lowerlayers@camunxcas11 ~]$ lspci | grep -i usb
>
> 00:02.0 USB Controller: nVidia Corporation CK804 USB Controller (rev a2)
>
> 00:02.1 USB Controller: nVidia Corporation CK804 USB Controller (rev a3)
>
>
> lsusb:
>
> Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
>
> Bus 002 Device 002: ID 0451:2077 Texas Instruments, Inc. TUSB2077 Hub
>
>
>
>
> My device is a full-speed device. So , stall packets are due to buggy
> USB 2.0 hub?
It's entirely possible that the stall packets are created by the hub.
When a full-speed device is connected to a USB-2 hub, and the device
fails to respond to a packet sent by the host, the hub reports this
failure as a stall.
When the device is connected to an OHCI controller, such failures would
be reported in a different way, such as a -EPROTO or -EILSEQ status.
> Is there a chance of getting stall packets “If the device runs at low
> speed or full speed and is connected through a USB-2.0 hub”? If so it
> looks like hub driver issue right?
If the problem is that the device fails to respond to a packet then it
is an issue with the device.
> If the hub is the problem… what will be the better solution? Is it
> possible to change internal hub?
No, it is not possible.
Alan Stern
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