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HID: handle cases of volume knobs generating relative values 

There are some devices (for example Dell Multimedia Keyboard SK-8135) that have
a volume control knob which generates relative events instead of absolute.
hid-input maps them to ABS_VOLUME. HUT pages don't restrict volume to absolute
values.

Adding REL_VOLUME doesn't seem feasible, nothing knows how to handle it. This
patch translates relative ABS_VOLUME events into appropriate number of series
of VOLUME_UP or VOLUME_DOWN events respectively, so that userspace sees the
correct values in the end.

kernel.org bugzilla 5233

Reported-by: Jochen Eisinger <jochen@penguin-breeder.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Jiri Kosina 2007-07-04 16:45:59 +02:00
parent 3c5f4b25f3
commit 2c1d8aea2c
1 changed files with 25 additions and 0 deletions
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25
drivers/hid/hid-input.c
View File

@ -882,6 +882,16 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
field->dpad = usage->code;
}
/* for those devices which produce Consumer volume usage as relative,
* we emulate pressing volumeup/volumedown appropriate number of times
* in hidinput_hid_event()
*/
if ((usage->type == EV_ABS) && (field->flags & HID_MAIN_ITEM_RELATIVE) &&
(usage->code == ABS_VOLUME)) {
set_bit(KEY_VOLUMEUP, input->keybit);
set_bit(KEY_VOLUMEDOWN, input->keybit);
}
hid_resolv_event(usage->type, usage->code);
#ifdef CONFIG_HID_DEBUG
printk("\n");
@ -972,6 +982,21 @@ void hidinput_hid_event(struct hid_device *hid, struct hid_field *field, struct
if ((usage->type == EV_KEY) && (usage->code == 0)) /* Key 0 is "unassigned", not KEY_UNKNOWN */
return;
if ((usage->type == EV_ABS) && (field->flags & HID_MAIN_ITEM_RELATIVE) &&
(usage->code == ABS_VOLUME)) {
int count = abs(value);
int direction = value > 0 ? KEY_VOLUMEUP : KEY_VOLUMEDOWN;
int i;
for (i = 0; i < count; i++) {
input_event(input, EV_KEY, direction, 1);
input_sync(input);
input_event(input, EV_KEY, direction, 0);
input_sync(input);
}
return;
}
input_event(input, usage->type, usage->code, value);
if ((field->flags & HID_MAIN_ITEM_RELATIVE) && (usage->type == EV_KEY))