Re: [PATCH 2/3] hid: 3m: Convert to MT slots

From: Stéphane Chatty
Date: Mon Sep 20 2010 - 15:43:50 EST



Le 28 août 10 à 16:29, Henrik Rydberg a écrit :

The Microtouch controller is capable of doing finger tracking on
up to 60 fingers. To reduce bandwidth and cpu usage, convert the
driver to use the MT slots protocol.

As I understand it, this patch actually has three roles:
1. improving the evdev parameters of the device
2. cleaning the protocol to get rid of useless MISC/SCANCODE messages
3. convert the protocol to MT slots


+#define SN_MOVE 2048
+#define SN_WIDTH 128


In the long run, it might be useful to comment these signal/noise constants



hid_map_usage(hi, usage, bit, max, EV_KEY, BTN_TOUCH);
+ input_set_capability(hi->input, EV_KEY, BTN_TOUCH);

{
+ /* tell hid-input to skip setup of these event types */
if (usage->type == EV_KEY || usage->type == EV_ABS)
- clear_bit(usage->code, *bit);
-
- return 0;
+ set_bit(usage->type, hi->input->evbit);
+ return -1;
}


I understand this as a trick to get rid of MISC/SCANCODEs that are added for every EV_KEY message, consequence of a rule in hid-input.c. Wouldn't it be simpler to improve the rule than to work around it?

Cheers,

St.

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