On Jan 17, 2019, at 10:42 PM, Benjamin Tissoires [off-list ref] wrote:

Hi Kai-Heng,

On Thu, Jan 17, 2019 at 10:30 AM Kai-Heng Feng
[off-list ref] wrote:

quoted

There are some new HP laptops with Elantech touchpad don't support
multitouch.

Both ETP_BUS_SMB_HST_NTFY_ONLY and ETP_BUS_PS2_SMB_HST_NTFY devices can
use SMBus to support 5 fingers touch, so we need to chech them too.

So use elantech_use_host_notify() to do a more thouroughly check.

Signed-off-by: Kai-Heng Feng <redacted>
---
drivers/input/mouse/elantech.c | 58 +++++++++++++++++-----------------
1 file changed, 29 insertions(+), 29 deletions(-)

diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
index 9fe075c137dc..5bcf1c147eb1 100644
--- a/drivers/input/mouse/elantech.c
+++ b/drivers/input/mouse/elantech.c

@@ -1799,6 +1799,34 @@ static int elantech_create_smbus(struct psmouse *psmouse,
                                 leave_breadcrumbs);

}

+static bool elantech_use_host_notify(struct psmouse *psmouse,
+                                    struct elantech_device_info *info)
+{
+       if (ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version))
+               return true;
+
+       switch (info->bus) {
+       case ETP_BUS_PS2_ONLY:
+               /* expected case */
+               break;
+       case ETP_BUS_SMB_ALERT_ONLY:
+               /* fall-through  */
+       case ETP_BUS_PS2_SMB_ALERT:
+               psmouse_dbg(psmouse, "Ignoring SMBus provider through alert protocol.\n");
+               break;
+       case ETP_BUS_SMB_HST_NTFY_ONLY:
+               /* fall-through  */
+       case ETP_BUS_PS2_SMB_HST_NTFY:
+               return true;
+       default:
+               psmouse_dbg(psmouse,
+                           "Ignoring SMBus bus provider %d.\n",
+                           info->bus);
+       }
+
+       return false;
+}
+
/**
 * elantech_setup_smbus - called once the PS/2 devices are enumerated
 * and decides to instantiate a SMBus InterTouch device.

@@ -1818,7 +1846,7 @@ static int elantech_setup_smbus(struct psmouse *psmouse,
                * i2c_blacklist_pnp_ids.
                * Old ICs are up to the user to decide.
                */
-               if (!ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version) ||
+               if (!elantech_use_host_notify(psmouse, info) ||

That was my initial approach of the series, but I ended up being more
conservative as this would flip all of the existing elantech SMBUS
capable touchpads to use elan_i2c.
And I didn't want to deal with 4/5 year old laptops that suddenly broke.

So I wonder if you can restrict this default change to the recent
laptops (let's say 2018+). Maybe by looking at their FW version or
something else in the DMI?

It was KT who told me that I should use ETP_BUS_PS2_SMB_HST_NTFY.

As for date, KT still knows better than me.

KT, 
Can you name a year which is safe enough to enable SMBus?

Kai-Heng

Cheers,
Benjamin

quoted

                   psmouse_matches_pnp_id(psmouse, i2c_blacklist_pnp_ids))
                       return -ENXIO;
       }

@@ -1838,34 +1866,6 @@ static int elantech_setup_smbus(struct psmouse *psmouse,
       return 0;

}

-static bool elantech_use_host_notify(struct psmouse *psmouse,
-                                    struct elantech_device_info *info)
-{
-       if (ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version))
-               return true;
-
-       switch (info->bus) {
-       case ETP_BUS_PS2_ONLY:
-               /* expected case */
-               break;
-       case ETP_BUS_SMB_ALERT_ONLY:
-               /* fall-through  */
-       case ETP_BUS_PS2_SMB_ALERT:
-               psmouse_dbg(psmouse, "Ignoring SMBus provider through alert protocol.\n");
-               break;
-       case ETP_BUS_SMB_HST_NTFY_ONLY:
-               /* fall-through  */
-       case ETP_BUS_PS2_SMB_HST_NTFY:
-               return true;
-       default:
-               psmouse_dbg(psmouse,
-                           "Ignoring SMBus bus provider %d.\n",
-                           info->bus);
-       }
-
-       return false;
-}
-
int elantech_init_smbus(struct psmouse *psmouse)
{
       struct elantech_device_info info;
--
2.17.1