Hi
Currently the Linux xhci driver will always try to enable a slot, if no slot is
available xhci will return a
"No slot available" error command completion code.
If the command completion code is anything else than "Success" for the enable
slot command, the driver
will print out the following error message:
"Error while assigning device slot ID"
"Max number of devices this xHCI host supports is %u."
This should be visible with dmesg
xhci_alloc_dev() returns 1 if slot was successfully enabled, 0 on failure.
xhci driver can not itself generate any popup messages, this is up to
userspace. If the userspace you are using
is supposed to generate some popup message for this then it's possible that the failing
"0" returned
by xhci_alloc_dev() is not properly propageated/translated through usb core,
the used usb libarary
and whatever other userspace components on top.
Regards
-Mathias
On 13.10.2015 18:34, Binu Thanka Kumar Chinna Thankam wrote:
Hi Mathias,
Could you please take a look on the below issue and provide your input on this.
Thanks and Regards
Binu
-----Original Message-----
From: Sarah Sharp [mailto:sarah.a.sh...@intel.com]
Sent: 13 October 2015 00:04
To: Binu Thanka Kumar Chinna Thankam
<binuthankakumar.chinnathan...@lnttechservices.com>
Cc: Sunil Kumar G <g.sunilku...@lnttechservices.com>; Badrinath Ramachandra
<badrinath.ramachan...@lnttechservices.com>; Nyman, Mathias <mathias.ny...@intel.com>
Subject: Re: Enumerating the USB device more than the capability of Host in the
Linux Platform
Please follow up with the new xHCI driver maintainer, Mathias Nyman
<mathias.ny...@intel.com>, and Cc the public Linux USB mailing list
<linux-usb@vger.kernel.org>.
Sarah Sharp
On Sun, Oct 11, 2015 at 02:50:31PM +0000, Binu Thanka Kumar Chinna Thankam
wrote:
Hi Sara,
In one of our XHCI Host DUT configurations, we have limited the max slots
supported by our xHCI host as 8.
With this configuration, we tried to test our XHCI DUT in FPGA with Linux
driver and we could see the interop tree with 8 devices is working fine.
We tried to do an experiment to check the behaviour of the System by connecting
the 9th device to the tree.
During this time we saw the 9th device is not enumerated by the system and no
message is displayed.
When we checked the PCI analyser trace to view the XHCI specific
transactions, we noticed the following.
Software tried to enumerate the device by sending the enable slot command for
the 9th slot which is not supported by our Host even though the Host indicated
the max slot as 8 through the HCSPARAMS1 register.
When that enable slot command for the 9 the device is processed by the Host, it
sends out a command completion event with completion code as Slot not
available error.
I would expect the Software should send a popup message which should indicate
that the device cannot be enumerated since it exceeds the capability of Host,
during this condition.
Could you please provide your input if any.
Thanks and Regards
BInu
L&T Technology Services Ltd
www.LntTechservices.com<http://www.lnttechservices.com/>
This Email may contain confidential or privileged information for the intended
recipient (s). If you are not the intended recipient, please do not use or
disseminate the information, notify the sender and delete it from your system.
L&T Technology Services Ltd
www.LntTechservices.com<http://www.lnttechservices.com/>
This Email may contain confidential or privileged information for the intended
recipient (s). If you are not the intended recipient, please do not use or
disseminate the information, notify the sender and delete it from your system.
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
