Hi Daniel, On Sun, Oct 9, 2011 at 2:20 AM, Daniel Drake <dsd@xxxxxxxxxx> wrote: > Currently, the synaptics driver puts the device into Absolute mode. > As explained in the synaptics documentation section 3.2, in this mode, > the device sends a continuous stream of packets at the maximum rate > to the host when the user's fingers are near or on the pad or > pressing buttons, and continues streaming for 1 second afterwards. > These packets are even sent when there is no new information to report, > even when they are duplicates of the previous packet. > > For embedded systems this is a bit much - it results in a huge > and uninterrupted stream of interrupts at high rate. > This patch seems reasonable, but I don't think your explanation is quite right. It is quite common for a user to move their finger around on a trackpad for several seconds continuously. This generates exactly the same "huge and uninterrupted stream of interrupts at a high rate" as fingers near the pad, idle on the pad, or after the pad is lifted. In other words, the peak *packet rate* is the same in absolute or relative mode. What changes is the *packet size*. Relative Mode uses a single 3-byte PS/2 packet, while Absolute Mode uses 2 3-byte PS/2 packets, resulting in double the number of bytes. The packets themselves are by default sent at 80 Hz (12.5ms/packet). Therefore, since the serio raw interrupts are per byte, Relative Mode has ~240 serio irq/s, whereas Absolute Mode has 480 irq/s. However, according to the "Synaptics TouchPad Interfacing Guide" (http://www.synaptics.com/sites/default/files/511-000275-01rA.pdf), you can achieve the same halving of the peak irq rate by changing the report rate from 80 to 40 Hz with the "Rate" bit of the "Mode Byte": 4.3 Mode Byte ... Rate (bit 6) The TouchPad typically generates 40 or 80 packets per second: • 80 packets per second, also known as full speed, is the default. The higher packet rate is preferable because it leads to the smoothest cursor motion. • 40 packets per second, also known as half speed, is used for slower hosts that cannot keep up with 80 packets per second. Also, the low packet rate mode does more internal data filtering and so may perform better in environments of extreme electrical noise. This bit is 0 to select half speed, or 1 to select full speed. The default setting for this bit in most TouchPad devices is 1. This bit is valid in both Relative and Absolute mode, although it may not be supported in all Synaptics products. Thus, you can keep the trackpad in Absolute mode, but reduce the report rate to 40Hz, resulting in the same 240 irq/s. This lets you handle tap-to-click and other gesture recognition up in userspace, for example, in xf86-input-synaptics X input driver, which is where many people argue that they belong. Have you ever experimented with this approach? There are a couple of possible downsides: (1) 40Hz is less than the typical 60Hz screen refresh rate, thus the cursor will not move as smoothly on the screen. This can actually be handled, however, with some pointer motion interpolation in user space. (2) At some point in time, xf86-input-synaptics had inter-packet timing hardcoded as "13ms", I don't remember the current status, but this clearly wouldn't be true anymore. -Daniel > This patch adds support for Relative mode, which can be selected through > a sysfs attribute. In this mode, the device does not send duplicate > packets and acts like a standard PS/2 mouse. However, synaptics-specific > functionality is still available, such as the ability to set the packet > rate, and rather than disabling gestures and taps at the hardware level > unconditionally, a 'synaptics_disable_gesture' sysfs attribute has > been added to allow control of this functionality. > > This solves a long standing OLPC issue: synaptics hardware enables > tap to click by default (even in the default relative mode), but we > have found this to be inappropriate for young children and first > time computer users. Enabling the synaptics driver disables tap-to-click, > but we have previously been unable to use this because it also enables > Absolute mode, which is too "spammy" for our desires and actually > overloads our EC with its continuous stream of packets. Now we can enable > the synaptics driver, disabling tap to click while retaining the less > noisy Relative mode. > > Signed-off-by: Daniel Drake <dsd@xxxxxxxxxx> > --- > drivers/input/mouse/psmouse-base.c | 2 +- > drivers/input/mouse/psmouse.h | 1 + > drivers/input/mouse/synaptics.c | 239 +++++++++++++++++++++++++++++------- > drivers/input/mouse/synaptics.h | 4 + > 4 files changed, 200 insertions(+), 46 deletions(-) > > diff --git a/drivers/input/mouse/psmouse-base.c b/drivers/input/mouse/psmouse-base.c > index 2246843..651dd4b 100644 > --- a/drivers/input/mouse/psmouse-base.c > +++ b/drivers/input/mouse/psmouse-base.c > @@ -124,7 +124,7 @@ struct psmouse_protocol { > * relevant events to the input module once full packet has arrived. > */ > > -static psmouse_ret_t psmouse_process_byte(struct psmouse *psmouse) > +psmouse_ret_t psmouse_process_byte(struct psmouse *psmouse) > { > struct input_dev *dev = psmouse->dev; > unsigned char *packet = psmouse->packet; > diff --git a/drivers/input/mouse/psmouse.h b/drivers/input/mouse/psmouse.h > index 593e910..7ceb3ea 100644 > --- a/drivers/input/mouse/psmouse.h > +++ b/drivers/input/mouse/psmouse.h > @@ -102,6 +102,7 @@ int psmouse_sliced_command(struct psmouse *psmouse, unsigned char command); > int psmouse_reset(struct psmouse *psmouse); > void psmouse_set_state(struct psmouse *psmouse, enum psmouse_state new_state); > void psmouse_set_resolution(struct psmouse *psmouse, unsigned int resolution); > +psmouse_ret_t psmouse_process_byte(struct psmouse *psmouse); > > struct psmouse_attribute { > struct device_attribute dattr; > diff --git a/drivers/input/mouse/synaptics.c b/drivers/input/mouse/synaptics.c > index 5538fc6..8b8bb8c 100644 > --- a/drivers/input/mouse/synaptics.c > +++ b/drivers/input/mouse/synaptics.c > @@ -32,6 +32,8 @@ > #include "psmouse.h" > #include "synaptics.h" > > +static int synaptics_reconnect(struct psmouse *psmouse); > + > /* > * The x/y limits are taken from the Synaptics TouchPad interfacing Guide, > * section 2.3.2, which says that they should be valid regardless of the > @@ -258,19 +260,48 @@ static int synaptics_query_hardware(struct psmouse *psmouse) > return 0; > } > > -static int synaptics_set_absolute_mode(struct psmouse *psmouse) > +static int synaptics_set_advanced_gesture_mode(struct psmouse *psmouse) > +{ > + static unsigned char param = 0xc8; > + struct synaptics_data *priv = psmouse->private; > + > + if (!SYN_CAP_ADV_GESTURE(priv->ext_cap_0c)) > + return 0; > + > + if (psmouse_sliced_command(psmouse, SYN_QUE_MODEL)) > + return -1; > + if (ps2_command(&psmouse->ps2dev, ¶m, PSMOUSE_CMD_SETRATE)) > + return -1; > + > + /* Advanced gesture mode also sends multi finger data */ > + priv->capabilities |= BIT(1); > + > + return 0; > +} > + > +static int synaptics_set_mode(struct psmouse *psmouse) > { > struct synaptics_data *priv = psmouse->private; > > - priv->mode = SYN_BIT_ABSOLUTE_MODE; > - if (SYN_ID_MAJOR(priv->identity) >= 4) > + priv->mode = 0; > + if (priv->absolute_mode) > + priv->mode |= SYN_BIT_ABSOLUTE_MODE; > + if (priv->disable_gesture) > priv->mode |= SYN_BIT_DISABLE_GESTURE; > + if (psmouse->rate >= 80) > + priv->mode |= SYN_BIT_HIGH_RATE; > if (SYN_CAP_EXTENDED(priv->capabilities)) > priv->mode |= SYN_BIT_W_MODE; > > if (synaptics_mode_cmd(psmouse, priv->mode)) > return -1; > > + if (priv->absolute_mode && > + synaptics_set_advanced_gesture_mode(psmouse)) { > + printk(KERN_ERR "Advanced gesture mode init failed.\n"); > + return -1; > + } > + > return 0; > } > > @@ -289,25 +320,6 @@ static void synaptics_set_rate(struct psmouse *psmouse, unsigned int rate) > synaptics_mode_cmd(psmouse, priv->mode); > } > > -static int synaptics_set_advanced_gesture_mode(struct psmouse *psmouse) > -{ > - static unsigned char param = 0xc8; > - struct synaptics_data *priv = psmouse->private; > - > - if (!SYN_CAP_ADV_GESTURE(priv->ext_cap_0c)) > - return 0; > - > - if (psmouse_sliced_command(psmouse, SYN_QUE_MODEL)) > - return -1; > - if (ps2_command(&psmouse->ps2dev, ¶m, PSMOUSE_CMD_SETRATE)) > - return -1; > - > - /* Advanced gesture mode also sends multi finger data */ > - priv->capabilities |= BIT(1); > - > - return 0; > -} > - > /***************************************************************************** > * Synaptics pass-through PS/2 port support > ****************************************************************************/ > @@ -694,13 +706,45 @@ static psmouse_ret_t synaptics_process_byte(struct psmouse *psmouse) > /***************************************************************************** > * Driver initialization/cleanup functions > ****************************************************************************/ > -static void set_input_params(struct input_dev *dev, struct synaptics_data *priv) > +static void set_input_params(struct psmouse *psmouse, struct input_dev *dev, > + struct input_dev *old_dev) > { > + struct synaptics_data *priv = psmouse->private; > int i; > int fuzz = SYN_CAP_REDUCED_FILTERING(priv->ext_cap_0c) ? > SYN_REDUCED_FILTER_FUZZ : 0; > > + if (old_dev) { > + dev->name = old_dev->name; > + dev->phys = old_dev->phys; > + dev->id = old_dev->id; > + dev->dev.parent = old_dev->dev.parent; > + } > + > + /* Things that apply to both modes */ > __set_bit(INPUT_PROP_POINTER, dev->propbit); > + __set_bit(EV_KEY, dev->evbit); > + __set_bit(BTN_LEFT, dev->keybit); > + __set_bit(BTN_RIGHT, dev->keybit); > + > + if (SYN_CAP_MIDDLE_BUTTON(priv->capabilities)) > + __set_bit(BTN_MIDDLE, dev->keybit); > + > + if (!priv->absolute_mode) { > + /* Relative mode */ > + __set_bit(EV_REL, dev->evbit); > + __set_bit(REL_X, dev->relbit); > + __set_bit(REL_Y, dev->relbit); > + > + /* Relative mode follows standard PS/2 mouse protocol */ > + psmouse->protocol_handler = psmouse_process_byte; > + psmouse->pktsize = 3; > + return; > + } > + > + /* Absolute mode */ > + psmouse->protocol_handler = synaptics_process_byte; > + psmouse->pktsize = 6; > > __set_bit(EV_ABS, dev->evbit); > input_set_abs_params(dev, ABS_X, > @@ -732,20 +776,14 @@ static void set_input_params(struct input_dev *dev, struct synaptics_data *priv) > if (SYN_CAP_PALMDETECT(priv->capabilities)) > input_set_abs_params(dev, ABS_TOOL_WIDTH, 0, 15, 0, 0); > > - __set_bit(EV_KEY, dev->evbit); > __set_bit(BTN_TOUCH, dev->keybit); > __set_bit(BTN_TOOL_FINGER, dev->keybit); > - __set_bit(BTN_LEFT, dev->keybit); > - __set_bit(BTN_RIGHT, dev->keybit); > > if (SYN_CAP_MULTIFINGER(priv->capabilities)) { > __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit); > __set_bit(BTN_TOOL_TRIPLETAP, dev->keybit); > } > > - if (SYN_CAP_MIDDLE_BUTTON(priv->capabilities)) > - __set_bit(BTN_MIDDLE, dev->keybit); > - > if (SYN_CAP_FOUR_BUTTON(priv->capabilities) || > SYN_CAP_MIDDLE_BUTTON(priv->capabilities)) { > __set_bit(BTN_FORWARD, dev->keybit); > @@ -770,8 +808,117 @@ static void set_input_params(struct input_dev *dev, struct synaptics_data *priv) > } > } > > +static ssize_t attr_show_absolute(struct psmouse *psmouse, void *data, > + char *buf) > +{ > + struct synaptics_data *priv = psmouse->private; > + > + return sprintf(buf, "%c\n", priv->absolute_mode ? '1' : '0'); > +} > + > +static ssize_t attr_set_absolute(struct psmouse *psmouse, void *data, > + const char *buf, size_t len) > +{ > + struct synaptics_data *priv = psmouse->private; > + struct input_dev *old_dev = psmouse->dev; > + struct input_dev *new_dev; > + unsigned long value; > + int err = -1; > + > + if (strict_strtoul(buf, 10, &value)) > + return -EINVAL; > + > + if (value == priv->absolute_mode) > + return len; > + > + new_dev = input_allocate_device(); > + if (!new_dev) > + return -ENOMEM; > + > + psmouse_set_state(psmouse, PSMOUSE_INITIALIZING); > + > + priv->absolute_mode = !!value; > + if (synaptics_set_mode(psmouse)) { > + printk(KERN_ERR "Unable to initialize Synaptics hardware.\n"); > + goto err_try_restore; > + } > + > + set_input_params(psmouse, new_dev, psmouse->dev); > + > + psmouse_set_state(psmouse, PSMOUSE_CMD_MODE); > + > + err = input_register_device(new_dev); > + if (err) > + goto err_try_restore; > + > + psmouse->dev = new_dev; > + input_unregister_device(old_dev); > + > + return len; > + > +err_try_restore: > + input_free_device(new_dev); > + priv->absolute_mode = !value; > + synaptics_reconnect(psmouse); > + return err; > +} > + > +PSMOUSE_DEFINE_ATTR(synaptics_absolute_mode, S_IWUSR | S_IRUGO, NULL, > + attr_show_absolute, attr_set_absolute); > + > +static ssize_t attr_show_disable_gesture(struct psmouse *psmouse, void *data, > + char *buf) > +{ > + struct synaptics_data *priv = psmouse->private; > + > + return sprintf(buf, "%c\n", priv->disable_gesture ? '1' : '0'); > +} > + > +static ssize_t attr_set_disable_gesture(struct psmouse *psmouse, void *data, > + const char *buf, size_t len) > +{ > + struct synaptics_data *priv = psmouse->private; > + unsigned long value; > + > + if (strict_strtoul(buf, 10, &value)) > + return -EINVAL; > + > + if (!SYN_ID_DISGEST_SUPPORTED(priv->identity)) > + return -EOPNOTSUPP; > + > + if (value == priv->disable_gesture) > + return len; > + > + priv->disable_gesture = !!value; > + if (value) > + priv->mode |= SYN_BIT_DISABLE_GESTURE; > + else > + priv->mode &= ~SYN_BIT_DISABLE_GESTURE; > + > + if (synaptics_mode_cmd(psmouse, priv->mode)) > + return -EIO; > + > + return len; > +} > + > +PSMOUSE_DEFINE_ATTR(synaptics_disable_gesture, S_IWUSR | S_IRUGO, NULL, > + attr_show_disable_gesture, attr_set_disable_gesture); > + > +static struct attribute *syn_attributes[] = { > + &psmouse_attr_synaptics_absolute_mode.dattr.attr, > + &psmouse_attr_synaptics_disable_gesture.dattr.attr, > + NULL > +}; > + > +static struct attribute_group syn_attribute_group = { > + .attrs = syn_attributes, > +}; > + > static void synaptics_disconnect(struct psmouse *psmouse) > { > + sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj, > + &syn_attribute_group); > + > synaptics_reset(psmouse); > kfree(psmouse->private); > psmouse->private = NULL; > @@ -801,16 +948,11 @@ static int synaptics_reconnect(struct psmouse *psmouse) > return -1; > } > > - if (synaptics_set_absolute_mode(psmouse)) { > + if (synaptics_set_mode(psmouse)) { > printk(KERN_ERR "Unable to initialize Synaptics hardware.\n"); > return -1; > } > > - if (synaptics_set_advanced_gesture_mode(psmouse)) { > - printk(KERN_ERR "Advanced gesture mode reconnect failed.\n"); > - return -1; > - } > - > if (old_priv.identity != priv->identity || > old_priv.model_id != priv->model_id || > old_priv.capabilities != priv->capabilities || > @@ -890,6 +1032,7 @@ void __init synaptics_module_init(void) > int synaptics_init(struct psmouse *psmouse) > { > struct synaptics_data *priv; > + int err = -1; > > /* > * The OLPC XO has issues with Synaptics' absolute mode; similarly to > @@ -916,13 +1059,13 @@ int synaptics_init(struct psmouse *psmouse) > goto init_fail; > } > > - if (synaptics_set_absolute_mode(psmouse)) { > - printk(KERN_ERR "Unable to initialize Synaptics hardware.\n"); > - goto init_fail; > - } > + /* defaults */ > + priv->absolute_mode = 1; > + if (SYN_ID_DISGEST_SUPPORTED(priv->identity)) > + priv->disable_gesture = 1; > > - if (synaptics_set_advanced_gesture_mode(psmouse)) { > - printk(KERN_ERR "Advanced gesture mode init failed.\n"); > + if (synaptics_set_mode(psmouse)) { > + printk(KERN_ERR "Unable to initialize Synaptics hardware.\n"); > goto init_fail; > } > > @@ -933,7 +1076,7 @@ int synaptics_init(struct psmouse *psmouse) > SYN_ID_MAJOR(priv->identity), SYN_ID_MINOR(priv->identity), > priv->model_id, priv->capabilities, priv->ext_cap, priv->ext_cap_0c); > > - set_input_params(psmouse->dev, priv); > + set_input_params(psmouse, psmouse->dev, NULL); > > /* > * Encode touchpad model so that it can be used to set > @@ -945,12 +1088,10 @@ int synaptics_init(struct psmouse *psmouse) > psmouse->model = ((priv->model_id & 0x00ff0000) >> 8) | > (priv->model_id & 0x000000ff); > > - psmouse->protocol_handler = synaptics_process_byte; > psmouse->set_rate = synaptics_set_rate; > psmouse->disconnect = synaptics_disconnect; > psmouse->reconnect = synaptics_reconnect; > psmouse->cleanup = synaptics_reset; > - psmouse->pktsize = 6; > /* Synaptics can usually stay in sync without extra help */ > psmouse->resync_time = 0; > > @@ -968,11 +1109,19 @@ int synaptics_init(struct psmouse *psmouse) > psmouse->rate = 40; > } > > + err = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj, > + &syn_attribute_group); > + if (err) { > + dev_err(&psmouse->ps2dev.serio->dev, > + "Failed to create sysfs attributes (%d)", err); > + goto init_fail; > + } > + > return 0; > > init_fail: > kfree(priv); > - return -1; > + return err; > } > > bool synaptics_supported(void) > diff --git a/drivers/input/mouse/synaptics.h b/drivers/input/mouse/synaptics.h > index ca040aa..c6e01fa 100644 > --- a/drivers/input/mouse/synaptics.h > +++ b/drivers/input/mouse/synaptics.h > @@ -97,6 +97,7 @@ > #define SYN_ID_MINOR(i) (((i) >> 16) & 0xff) > #define SYN_ID_FULL(i) ((SYN_ID_MAJOR(i) << 8) | SYN_ID_MINOR(i)) > #define SYN_ID_IS_SYNAPTICS(i) ((((i) >> 8) & 0xff) == 0x47) > +#define SYN_ID_DISGEST_SUPPORTED(i) (SYN_ID_MAJOR(i) >= 4) > > /* synaptics special commands */ > #define SYN_PS_SET_MODE2 0x14 > @@ -144,6 +145,9 @@ struct synaptics_data { > unsigned char mode; /* current mode byte */ > int scroll; > > + unsigned int absolute_mode:1; /* run in Absolute mode */ > + unsigned int disable_gesture:1; /* disable gestures */ > + > struct serio *pt_port; /* Pass-through serio port */ > > struct synaptics_hw_state mt; /* current gesture packet */ > -- > 1.7.6.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-input" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
