çå: çå: [PATCH] input: alps-fix the issue the special alps trackpoint do not work.

[Xiaoxiao Liu]

Hi Pali,

Why it does not report input data?
--> The alps devices which detected to use the ALPS_PROTO_V8  contains ALPS touchpad and ALPS track point. 
     But the ALPS_PROTO_V8 do not support the track point device process. 
     When the track point was detected to use ALPS_PROTO_V8 ,the v8 process_packet method  alps_process_packet_ss4_v2 will reject to report the data because the v8 device is      not set the ALPS_DUALPOINT flag. 
     You can refer below code.

	/* Report trackstick */
	if (alps_get_pkt_id_ss4_v2(packet) == SS4_PACKET_ID_STICK) {
		if (!(priv->flags & ALPS_DUALPOINT)) {
			psmouse_warn(psmouse,
				     "Rejected trackstick packet from non DualPoint device");
			return;
		}
		...
		return;
	}

why is for non-ALPS trackpoints used ALPS driver?
--> the non-Alps track point is the ALPS touchpad, it is right to use the ALPS driver for ALPS touchpad.

The v8 protocol condition may modified  as below, it will be more easier to understand.

	 if (e7[0] == 0x73 && e7[1] == 0x03 && (e7[2] == 0x14 || e7[2] == 0x28) &&  (alps_check_is_trackpoint(psmouse) != 0)  ) {
 		protocol = &alps_v8_protocol_data;
	}

Best Regards
XiaoXiao Liu
sliuuxiaonxiao@xxxxxxxxx
xiaoxiao.liu-1@xxxxxxxxxxx

-----éäåä-----
åää: Pali RohÃr <pali.rohar@xxxxxxxxx> 
åéæé: Tuesday, May 21, 2019 5:46 PM
æää: Hui Wang <hui.wang@xxxxxxxxxxxxx>
æé: å ææ Xiaoxiao Liu <xiaoxiao.liu-1@xxxxxxxxxxx>; XiaoXiao Liu <sliuuxiaonxiao@xxxxxxxxx>; dmitry.torokhov@xxxxxxxxx; linux-input@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; æ æå Xiaojian Cao <xiaojian.cao@xxxxxxxxxxx>; zhangfp1@xxxxxxxxxx
äé: Re: çå: [PATCH] input: alps-fix the issue the special alps trackpoint do not work.

Hello!

On Tuesday 21 May 2019 10:26:47 Hui Wang wrote:
> Tested-by: Hui Wang <hui.wang@xxxxxxxxxxxxx>
> 
> On 2019/5/21 äå9:07, Xiaoxiao Liu wrote:
> > Add Pali RohÃr.
> > 
> > -----éäåä-----
> > åää: XiaoXiao Liu <sliuuxiaonxiao@xxxxxxxxx>
> > åéæé: Monday, May 20, 2019 7:02 PM
> > æää: dmitry.torokhov@xxxxxxxxx
> > æé: linux-input@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; 
> > hui.wang@xxxxxxxxxxxxx; æ æå Xiaojian Cao 
> > <xiaojian.cao@xxxxxxxxxxx>; zhangfp1@xxxxxxxxxx; å ææ Xiaoxiao Liu 
> > <xiaoxiao.liu-1@xxxxxxxxxxx>; XiaoXiao Liu 
> > <sliuuxiaonxiao@xxxxxxxxx>
> > äé: [PATCH] input: alps-fix the issue the special alps trackpoint do not work.
> > 
> > when the alps trackpoint is detected and using the 
> > alps_v8_protocol_data procotol, the alps driver will not report the input data.

Why it does not report input data?

> > solution: use standard mouse driver instead of alps driver when the specail trackpoint was detected.

This looks like an (undocumented) hack or workaround. Not a solution.

> > Signed-off-by: XiaoXiao Liu <sliuuxiaonxiao@xxxxxxxxx>
> > ---
> >   drivers/input/mouse/alps.c | 23 ++++++++++++++++++++++-
> >   1 file changed, 22 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/input/mouse/alps.c b/drivers/input/mouse/alps.c 
> > index 0a6f7ca883e7..516ae1d0eb17 100644
> > --- a/drivers/input/mouse/alps.c
> > +++ b/drivers/input/mouse/alps.c
> > @@ -24,7 +24,7 @@
> >   #include "psmouse.h"
> >   #include "alps.h"
> > -
> > +#include "trackpoint.h"
> >   /*
> >    * Definitions for ALPS version 3 and 4 command mode protocol
> >    */
> > @@ -2864,6 +2864,22 @@ static const struct alps_protocol_info *alps_match_table(unsigned char *e7,
> >   	return NULL;
> >   }
> > +int alps_check_is_trackpoint(struct psmouse *psmouse) {
> > +	u8 param[2] = { 0 };
> > +	int error;
> > +
> > +	error = ps2_command(&psmouse->ps2dev,
> > +			    param, MAKE_PS2_CMD(0, 2, TP_READ_ID));
> > +	if (error)
> > +		return error;
> > +
> > +	if (param[0] == TP_VARIANT_ALPS)
> > +		return 0;
> > +	psmouse_warn(psmouse, "It is not alps trackpoint.\n");
> > +	return -ENODEV;
> > +}

So, this function returns 0 when detected ALPS trackpoint and -ENODEV when not.

> > +
> >   static int alps_identify(struct psmouse *psmouse, struct alps_data *priv)  {
> >   	const struct alps_protocol_info *protocol; @@ -2912,6 +2928,11 @@ static int alps_identify(struct psmouse *psmouse, struct alps_data *priv)
> >   			protocol = &alps_v3_protocol_data;
> >   		} else if (e7[0] == 0x73 && e7[1] == 0x03 &&
> >   			   (e7[2] == 0x14 || e7[2] == 0x28)) {
> > +				if (alps_check_is_trackpoint(psmouse) == 0) {
> > +					psmouse_warn(psmouse,
> > +					"It is alps trackpoint, use the standard mouse driver.\n");
> > +					return -EINVAL;

And here I'm lost. If we have *not* detected ALPS trackpoint then if block is not called which means that ALPS driver is used.

So why is for non-ALPS trackpoints used ALPS driver? This does not seem like a correct...

And when we have detected ALPS trackpoint (return value 0) then standard mouse driver is used and returned -EINVAL. This seems strange too.

So either this code is wrong or there are missing more details for explaining this strange logic. But still this looks like a hack not a proper fix/solution.

> > +				}
> >   			protocol = &alps_v8_protocol_data;
> >   		} else if (e7[0] == 0x73 && e7[1] == 0x03 && e7[2] == 0xc8) {
> >   			protocol = &alps_v9_protocol_data;
> > --
> > 2.20.1
> > 

--
Pali RohÃr
pali.rohar@xxxxxxxxx