[haiku-bugs] Re: [Haiku] #7354: usb_hid tablet support
- From: "caz_haiku" <trac@xxxxxxxxxxxx>
- Date: Sun, 13 Mar 2011 01:28:02 -0000
#7354: usb_hid tablet support
---------------------------+-----------------------
Reporter: lt_henry | Owner: mmlr
Type: enhancement | Status: new
Priority: normal | Milestone: R1
Component: Drivers/USB | Version: R1/alpha2
Resolution: | Keywords: usb_hid
Blocked By: | Blocking:
Has a Patch: 1 | Platform: All
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Comment (by caz_haiku):
mmlr, Good work on usb_hid by the way. i've looked at the
HIDCollection.cpp and HIDParser.cpp. In HIDParser.cpp when an
ITEM_TYPE_LOCAL is detected and then the item->tag is an
ITEM_TAG_LOCAL_USAGE should the code be as follows,
:)
value->u.s.usage_page = globalState.usage_page;[[BR]]
value->u.s.usage_id = data;
The code as it is now is[[BR]]
value->u.extended = data;
As far as i understand when an ITEM_TAG_LOCAL_USAGE is declared then it
should have the usage page of the previously declared global usage page(Am
i right ?). Also when a new HIDCollection is created when the item->tag
is ITEM_TAG_MAIN_COLLECTION the localstate is always empty when it's
created for the first time. This happens in the following situation,
USAGE_PAGE(Generic Desktop) type global[[BR]]
USAGE(GamePad) type local[[BR]]
Then when an item of ITEM_TAG_MAIN_COLLECTION is found for the first time,
the localState.usage_stack is passed to HIDCollection but it's empty
because the localState.usage_stack hasn't been initialized to point to
usageStack.[[BR]]
I've modified the code as follows,
if (item->tag == ITEM_TAG_MAIN_COLLECTION) {[[BR]]
localState.usage_stack = usageStack;[[BR]]
localState.usage_stack_used = usageStackUsed;[[BR]]
// then the code continues as normal.[[BR]]
By doing this modification the HIDCollection now at least has access to
the correct USAGE_PAGE and USAGE_ID for the devices type we are trying to
get.
--
Ticket URL: <http://dev.haiku-os.org/ticket/7354#comment:5>
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