-----Original Message-----
From: Kai-Heng Feng [mailto:kai.heng.feng@canonical.com] 
Sent: Monday, January 21, 2019 12:28 PM
To: 廖崇榮
Cc: Benjamin Tissoires; Dmitry Torokhov; open list:HID CORE LAYER; lkml
Subject: Re: [PATCH 1/1] Input: elantech: Use SMBus based on bus info

On Jan 18, 2019, at 17:29, 廖崇榮 [off-list ref] wrote:



-----Original Message-----
From: Kai Heng Feng [mailto:kai.heng.feng@canonical.com]
Sent: Friday, January 18, 2019 12:15 AM
To: Benjamin Tissoires
Cc: Dmitry Torokhov; 廖崇榮; open list:HID CORE LAYER; lkml
Subject: Re: [PATCH 1/1] Input: elantech: Use SMBus based on bus info

quoted

On Jan 17, 2019, at 10:42 PM, Benjamin Tissoires

[off-list ref] wrote:

quoted

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,

quoted

quoted

                                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");

quoted

quoted

+               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,

quoted

quoted

               * 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?

I have discussed it internally. 
The internal rule for FW's SMbus implementation is stable after 2018 
If you meet some special case, please let me know.

Thanks for the info. I’ll use this for the V2 patch.

BTW, The SMbus supporting is requested by HP this time, and there are 
plenty of HP laptop use old IC which doesn't meet " 
ETP_NEW_IC_SMBUS_HOST_NOTIFY”.

One more question, does ETP_BUS_SMB_HST_NTFY_ONLY means it should stick to SMBus, because it doesn’t support PS/2?

I’d like to merge all checks into elantech_use_host_notify() but ETP_BUS_SMB_HST_NTFY_ONLY caught my attention.

ETP_BUS_SMB_HST_NTFY_ONLY is for our previous planning but it never happen so far, and it won't happen in the future.
There are two cases for our released touchpad and they are " ETP_BUS_PS2_ONLY" and " ETP_BUS_PS2_SMB_HST_NTFY".

Thanks
KT

Kai-Heng

Elan touchpad works well in PS/2 for HP, because it don't support 
TrackPoint.
You may let old HP platform work as PS/2 for safety.

Thanks
KT

Kai-Heng

quoted

Cheers,
Benjamin

quoted

                  psmouse_matches_pnp_id(psmouse,

i2c_blacklist_pnp_ids))

quoted

quoted

                      return -ENXIO;
      }

@@ -1838,34 +1866,6 @@ static int elantech_setup_smbus(struct 

psmouse

*psmouse,

quoted

quoted

      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");

quoted

quoted

-               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