On 09.10.2018 21:57, Alan Stern wrote:
On Tue, 9 Oct 2018, Dmitry Malkin wrote:
Hi guys,
Could someone can give me a hint to this question:
if there are multiple connected USB devices (multiple ports with set
PORTSC.CCS bit) to xHCI and I issue the very first enable slot command
which port will be "enabled"?
The "Enable slot" command name can be bit misleading, think of it more as
"obtain/request/allocate an empty slot from xHC hardware".
It's not enabling any port.
After this the xhci driver allocates a slot context for the slot.
Route String and other values need to be set to the slot context
before issuing an address device command.
-Mathias
I don't see anything regarding this in specification (also I cannot find
anything like this in linux xhci driver).
See the description of the Route String and the Root Hub Port Number
entries in the slot context.
Alan Stern
Motivation is just simple: if I run into situation where I need to reset
device through PORTSC how can I distinguish between different ports?
