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Date: Wed, 9 Mar 2011 12:22:55 +0100
From: "Henrik Rydberg" <rydberg@...omail.se>
To: Benjamin Tissoires <benjamin.tissoires@...c.fr>
Cc: Dmitry Torokhov <dmitry.torokhov@...il.com>,
Jiri Kosina <jkosina@...e.cz>,
Stephane Chatty <chatty@...-enac.fr>,
linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/4] hid-multitouch: Auto detection of maxcontacts
On Tue, Mar 08, 2011 at 05:32:56PM +0100, Benjamin Tissoires wrote:
> This patch enables support of autodetection of maxcontacts.
> We can still manually provide maxcontact in case the device
> lies on it.
>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...c.fr>
> ---
> drivers/hid/hid-multitouch.c | 43 ++++++++++++++++++++++++++++-------------
> 1 files changed, 29 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
> index 65e7f20..363ca08 100644
> --- a/drivers/hid/hid-multitouch.c
> +++ b/drivers/hid/hid-multitouch.c
> @@ -38,6 +38,8 @@ MODULE_LICENSE("GPL");
> #define MT_QUIRK_VALID_IS_INRANGE (1 << 4)
> #define MT_QUIRK_VALID_IS_CONFIDENCE (1 << 5)
>
> +#define MT_CONTACTMAX_DEFAULT 11
> +
I think this one can be removed, se below.
> struct mt_slot {
> __s32 x, y, p, w, h;
> __s32 contactid; /* the device ContactID assigned to this slot */
> @@ -53,8 +55,9 @@ struct mt_device {
> __s8 inputmode; /* InputMode HID feature, -1 if non-existent */
> __u8 num_received; /* how many contacts we received */
> __u8 num_expected; /* expected last contact index */
> + __u8 maxcontacts;
> bool curvalid; /* is the current contact valid? */
> - struct mt_slot slots[0]; /* first slot */
> + struct mt_slot *slots;
> };
>
> struct mt_class {
> @@ -87,12 +90,12 @@ static int cypress_compute_slot(struct mt_device *td)
> static int find_slot_from_contactid(struct mt_device *td)
> {
> int i;
> - for (i = 0; i < td->mtclass->maxcontacts; ++i) {
> + for (i = 0; i < td->maxcontacts; ++i) {
> if (td->slots[i].contactid == td->curdata.contactid &&
> td->slots[i].touch_state)
> return i;
> }
> - for (i = 0; i < td->mtclass->maxcontacts; ++i) {
> + for (i = 0; i < td->maxcontacts; ++i) {
> if (!td->slots[i].seen_in_this_frame &&
> !td->slots[i].touch_state)
> return i;
> @@ -105,8 +108,7 @@ static int find_slot_from_contactid(struct mt_device *td)
>
> struct mt_class mt_classes[] = {
> { .name = MT_CLS_DEFAULT,
> - .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP,
> - .maxcontacts = 10 },
> + .quirks = MT_QUIRK_NOT_SEEN_MEANS_UP },
Keeping .maxcontacts at two here seems sensible
> { .name = MT_CLS_DUAL_INRANGE_CONTACTID,
> .quirks = MT_QUIRK_VALID_IS_INRANGE |
> MT_QUIRK_SLOT_IS_CONTACTID,
> @@ -126,9 +128,22 @@ struct mt_class mt_classes[] = {
> static void mt_feature_mapping(struct hid_device *hdev,
> struct hid_field *field, struct hid_usage *usage)
> {
> - if (usage->hid == HID_DG_INPUTMODE) {
> - struct mt_device *td = hid_get_drvdata(hdev);
> + struct mt_device *td = hid_get_drvdata(hdev);
> +
> + switch (usage->hid) {
> + case HID_DG_INPUTMODE:
> td->inputmode = field->report->id;
> + break;
> + case HID_DG_CONTACTMAX:
> + td->maxcontacts = *(field->value);
> + if (td->mtclass->maxcontacts)
if (td->mtclass->maxcontacts > td->maxcontacts)
> + /* check if the maxcontacts is given by the class */
> + td->maxcontacts = td->mtclass->maxcontacts;
> +
> + if (!td->maxcontacts)
> + td->maxcontacts = MT_CONTACTMAX_DEFAULT;
this part can be then dropped
> +
> + break;
> }
> }
>
> @@ -186,8 +201,7 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
> td->last_slot_field = usage->hid;
> return 1;
> case HID_DG_CONTACTID:
> - input_mt_init_slots(hi->input,
> - td->mtclass->maxcontacts);
> + input_mt_init_slots(hi->input, td->maxcontacts);
> td->last_slot_field = usage->hid;
> return 1;
> case HID_DG_WIDTH:
> @@ -268,7 +282,7 @@ static void mt_complete_slot(struct mt_device *td)
> if (td->curvalid) {
> int slotnum = mt_compute_slot(td);
>
> - if (slotnum >= 0 && slotnum < td->mtclass->maxcontacts)
> + if (slotnum >= 0 && slotnum < td->maxcontacts)
> td->slots[slotnum] = td->curdata;
> }
> td->num_received++;
> @@ -283,7 +297,7 @@ static void mt_emit_event(struct mt_device *td, struct input_dev *input)
> {
> int i;
>
> - for (i = 0; i < td->mtclass->maxcontacts; ++i) {
> + for (i = 0; i < td->maxcontacts; ++i) {
> struct mt_slot *s = &(td->slots[i]);
> if ((td->mtclass->quirks & MT_QUIRK_NOT_SEEN_MEANS_UP) &&
> !s->seen_in_this_frame) {
> @@ -415,9 +429,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
> */
> hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
>
> - td = kzalloc(sizeof(struct mt_device) +
> - mtclass->maxcontacts * sizeof(struct mt_slot),
> - GFP_KERNEL);
> + td = kzalloc(sizeof(struct mt_device), GFP_KERNEL);
> if (!td) {
> dev_err(&hdev->dev, "cannot allocate multitouch data\n");
> return -ENOMEM;
> @@ -434,6 +446,9 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
> if (ret)
> goto fail;
>
> + td->slots = kzalloc(td->maxcontacts * sizeof(struct mt_slot),
> + GFP_KERNEL);
> +
Don't we have a race problem here? It seems the device is started at
this point, so I worry that events will be handled when slots is still
NULL.
> mt_set_input_mode(hdev);
>
> return 0;
> --
> 1.7.4
>
Thanks,
Henrik
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