On 31/05/2016 16:34, Alan Stern wrote:
On Tue, 31 May 2016, Mathias Nyman wrote:
xhci specs say that port will move from Disconnected (PLS = RX_DETECT) to
Polling if "SuperSpeed far-end receiver terminations are detected"
From power-off state (PP=0) the connect status changes are only reported
if OCA is set so it seems that is not an option.
I'm looking at the capture log and if I understand it correcty, in frame
49 SET FEATURE, PLS = ss.disabled (xhci will write PORT_PED bit)
59 SET FEATURE, PLS = RxDetect (xhci will set pls=RxDetect)
.. get_port_status, nothing set, no changes reported (several of these)
73 SET FEATURE -> Port remote wake mask
.. get_port status reports Connected, enabled and port status change event
Could it be that setting the port remote wake mask somehow triggers the
connect status change event? It's the first time we write to PORTSC for
this port after setting link state to rx.detect
It's possible, but I doubt it. More likely it just takes a few hundred
ms for the RxDetect link training to realize there is a connection.
Marco, you can check whether this is true by doing (as root):
echo on >/sys/bus/usb/devices/usb4/power/control
before starting your test.
Alan Stern
Hi,
Sorry for my late reply but I've been very busy this week.
You can find the new captures in the same directory. Or just use the
following direct links:
https://drive.google.com/open?id=0B2tgr9hETOtgTEU1Qmc2eWNIYlE
https://drive.google.com/open?id=0B2tgr9hETOtgZUV2TkZRRGJjMWs
I could not notice any difference though. Anyway I'm happy to test
patches if you want to try changes.
Thank you,
Marco
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