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Commit cdd49a85 authored by Nikolai Kondrashov's avatar Nikolai Kondrashov Committed by Jiri Kosina
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HID: waltop: comment on tablet modes



Add a comment on modes supported by Waltop tablets - a knowledge extracted
from the outdated official driver, but not yet used by this driver.

Signed-off-by: default avatarNikolai Kondrashov <spbnick@gmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent 30311549
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+27 −2
Original line number Diff line number Diff line
@@ -17,13 +17,38 @@

#include "hid-ids.h"

/*
 * There exists an official driver on the manufacturer's website, which
 * wasn't submitted to the kernel, for some reason. The official driver
 * doesn't seem to support extra features of some tablets, like wheels.
 *
 * It shows that the feature report ID 2 could be used to control any waltop
 * tablet input mode, switching it between "default", "tablet" and "ink".
 *
 * This driver only uses "default" mode for all the supported tablets. This
 * mode tries to be HID-compatible (not very successfully), but cripples the
 * resolution of some tablets.
 *
 * The "tablet" mode uses some proprietary, yet decipherable protocol, which
 * represents the correct resolution, but is possibly HID-incompatible (i.e.
 * indescribable by a report descriptor).
 *
 * The purpose of the "ink" mode is unknown.
 *
 * The feature reports needed for switching to each mode are these:
 *
 * 02 16 00     default
 * 02 16 01     tablet
 * 02 16 02     ink
 */

/*
 * Original Slim Tablet 5.8 inch report descriptor.
 *
 * All the reports except the report with ID 16 (the stylus) are unused,
 * possibly because the tablet is not configured to, or because they were
 * just copied from a more capable model. The purpose of features described
 * for report ID 2 is unknown.
 * just copied from a more capable model. The full purpose of features
 * described for report ID 2 is unknown.
 *
 * The stylus buttons are described as three bit fields, whereas actually
 * it's an "array", i.e. they're reported as button numbers (1, 2 and 3).