Re: [REGRESSION] Touchpad failure after e7348396c6d5 ("Input: ALPS - fix V8+ protocol handling (73 03 28)")

[Takashi Iwai]

On Thu, 20 Jul 2017 11:20:20 +0200,
Masaki Ota wrote:
> 
> Hi, Takashi-san,
> 
> That's great! 
> 
> Actually, SS4 PLUS device is a little different from SS4 device.
> I added SS4 PLUS code as below.
> Could you try it?

Yes, it works as expected.  Feel free to take:
  Tested-by: Takashi Iwai <tiwai@xxxxxxx>

> And I still wonder why this issue does not happen on original code though X value is so large.

Which original code are you referring to?
The bug manifests itself only for decoding multi-touch events.


thanks,

Takashi

> 
> --- a/drivers/input/mouse/alps.c
> +++ b/drivers/input/mouse/alps.c
> @@ -1210,14 +1210,24 @@ static int alps_decode_ss4_v2(struct alps_fields *f,
>  
>  	case SS4_PACKET_ID_TWO:
>  		if (priv->flags & ALPS_BUTTONPAD) {
> -			f->mt[0].x = SS4_BTL_MF_X_V2(p, 0);
> +			if (IS_SS4PLUS_DEV(priv->dev_id)) {
> +				f->mt[0].x = SS4_PLUS_BTL_MF_X_V2(p, 0);
> +				f->mt[1].x = SS4_PLUS_BTL_MF_X_V2(p, 1);
> +			} else {
> +				f->mt[0].x = SS4_BTL_MF_X_V2(p, 0);
> +				f->mt[1].x = SS4_BTL_MF_X_V2(p, 1);
> +			}
>  			f->mt[0].y = SS4_BTL_MF_Y_V2(p, 0);
> -			f->mt[1].x = SS4_BTL_MF_X_V2(p, 1);
>  			f->mt[1].y = SS4_BTL_MF_Y_V2(p, 1);
>  		} else {
> -			f->mt[0].x = SS4_STD_MF_X_V2(p, 0);
> +			if (IS_SS4PLUS_DEV(priv->dev_id)) {
> +				f->mt[0].x = SS4_PLUS_STD_MF_X_V2(p, 0);
> +				f->mt[1].x = SS4_PLUS_STD_MF_X_V2(p, 1);
> +			} else {
> +				f->mt[0].x = SS4_STD_MF_X_V2(p, 0);
> +				f->mt[1].x = SS4_STD_MF_X_V2(p, 1);
> +			}
>  			f->mt[0].y = SS4_STD_MF_Y_V2(p, 0);
> -			f->mt[1].x = SS4_STD_MF_X_V2(p, 1);
>  			f->mt[1].y = SS4_STD_MF_Y_V2(p, 1);
>  		}
>  		f->pressure = SS4_MF_Z_V2(p, 0) ? 0x30 : 0;
> @@ -1234,16 +1244,27 @@ static int alps_decode_ss4_v2(struct alps_fields *f,
>  
>  	case SS4_PACKET_ID_MULTI:
>  		if (priv->flags & ALPS_BUTTONPAD) {
> -			f->mt[2].x = SS4_BTL_MF_X_V2(p, 0);
> +			if (IS_SS4PLUS_DEV(priv->dev_id)) {
> +				f->mt[0].x = SS4_PLUS_BTL_MF_X_V2(p, 0);
> +				f->mt[1].x = SS4_PLUS_BTL_MF_X_V2(p, 1);
> +			} else {
> +				f->mt[2].x = SS4_BTL_MF_X_V2(p, 0);
> +				f->mt[3].x = SS4_BTL_MF_X_V2(p, 1);
> +			}
> +
>  			f->mt[2].y = SS4_BTL_MF_Y_V2(p, 0);
> -			f->mt[3].x = SS4_BTL_MF_X_V2(p, 1);
>  			f->mt[3].y = SS4_BTL_MF_Y_V2(p, 1);
>  			no_data_x = SS4_MFPACKET_NO_AX_BL;
>  			no_data_y = SS4_MFPACKET_NO_AY_BL;
>  		} else {
> -			f->mt[2].x = SS4_STD_MF_X_V2(p, 0);
> +			if (IS_SS4PLUS_DEV(priv->dev_id)) {
> +				f->mt[0].x = SS4_PLUS_STD_MF_X_V2(p, 0);
> +				f->mt[1].x = SS4_PLUS_STD_MF_X_V2(p, 1);
> +			} else {
> +				f->mt[0].x = SS4_STD_MF_X_V2(p, 0);
> +				f->mt[1].x = SS4_STD_MF_X_V2(p, 1);
> +			}
>  			f->mt[2].y = SS4_STD_MF_Y_V2(p, 0);
> -			f->mt[3].x = SS4_STD_MF_X_V2(p, 1);
>  			f->mt[3].y = SS4_STD_MF_Y_V2(p, 1);
>  			no_data_x = SS4_MFPACKET_NO_AX;
>  			no_data_y = SS4_MFPACKET_NO_AY;
> @@ -2536,8 +2557,8 @@ static int alps_set_defaults_ss4_v2(struct psmouse *psmouse,
>  
>  	memset(otp, 0, sizeof(otp));
>  
> -	if (alps_get_otp_values_ss4_v2(psmouse, 0, &otp[0][0]) ||
> -	    alps_get_otp_values_ss4_v2(psmouse, 1, &otp[1][0]))
> +	if (alps_get_otp_values_ss4_v2(psmouse, 1, &otp[1][0]) ||
> +	    alps_get_otp_values_ss4_v2(psmouse, 0, &otp[0][0]))
>  		return -1;
>  
>  	alps_update_device_area_ss4_v2(otp, priv);
> diff --git a/drivers/input/mouse/alps.h b/drivers/input/mouse/alps.h
> index 4334f2805d93..75542199edda 100644
> --- a/drivers/input/mouse/alps.h
> +++ b/drivers/input/mouse/alps.h
> @@ -99,6 +99,10 @@ enum SS4_PACKET_ID {
>  				 ((_b[1 + _i * 3]  << 5) & 0x1F00)	\
>  				)
>  
> +#define SS4_PLUS_STD_MF_X_V2(_b, _i) (((_b[0 + (_i) * 3] << 4) & 0x0070) | \
> +				 ((_b[1 + (_i) * 3]  << 4) & 0x0F80)	\
> +				)
> +
>  #define SS4_STD_MF_Y_V2(_b, _i)	(((_b[1 + (_i) * 3] << 3) & 0x0010) |	\
>  				 ((_b[2 + (_i) * 3] << 5) & 0x01E0) |	\
>  				 ((_b[2 + (_i) * 3] << 4) & 0x0E00)	\
> @@ -108,6 +112,10 @@ enum SS4_PACKET_ID {
>  				 ((_b[0 + (_i) * 3] >> 3) & 0x0010)	\
>  				)
>  
> +#define SS4_PLUS_BTL_MF_X_V2(_b, _i) (SS4_PLUS_STD_MF_X_V2(_b, _i) |	\
> +				 ((_b[0 + (_i) * 3] >> 4) & 0x0008)	\
> +				)
> +
>  #define SS4_BTL_MF_Y_V2(_b, _i)	(SS4_STD_MF_Y_V2(_b, _i) | \
>  				 ((_b[0 + (_i) * 3] >> 3) & 0x0008)	\
>  				)
> --
> 
> Best Regards,
> Masaki Ota
> -----Original Message-----
> From: Takashi Iwai [mailto:tiwai@xxxxxxx] 
> Sent: Wednesday, July 19, 2017 5:57 PM
> To: Paul Donohue <linux-kernel@xxxxxxxxxx>
> Cc: Laura Abbott <labbott@xxxxxxxxxx>; åç çå Masaki Ota <masaki.ota@xxxxxxxxxxx>; Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>; Pali Rohar <pali.rohar@xxxxxxxxx>; Nick Fletcher <nick.m.fletcher@xxxxxxxxx>; linux-input@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; scott.s.lowe@xxxxxxxxx
> Subject: Re: [REGRESSION] Touchpad failure after e7348396c6d5 ("Input: ALPS - fix V8+ protocol handling (73 03 28)")
> 
> On Wed, 12 Jul 2017 18:28:41 +0200,
> Paul Donohue wrote:
> > 
> > On Wed, Jul 12, 2017 at 09:16:43AM +0200, Takashi Iwai wrote:
> > > On Tue, 11 Jul 2017 21:58:21 +0200,
> > > Paul Donohue wrote:
> > > > 
> > > > On Tue, Jul 11, 2017 at 05:50:07PM +0200, Takashi Iwai wrote:
> > > > > Hi, just joining to the party in the middle, as I'm also facing 
> > > > > the same problem on Dell E7270 laptop.  Has this issue already 
> > > > > been addressed?
> > > > > 
> > > > > If not, the following was my result:
> > > > > 
> > > > > - the first patch slowed the pointer movement a lot, it's even slower
> > > > >   than the old kernel (e.g. 4.4.x).
> > > > >   The two finger scroll works fine on all touchpad area now.
> > > > > 
> > > > > - the second patch made the pointer movement even faster than now (as
> > > > >   I feel, not quite sure).  The two finger scroll doesn't work at the
> > > > >   right side of the touchpad.
> > > > > 
> > > > > 
> > > > > The kernel output from the first patch is below:
> > > > >   psmouse serio1: alps: test1 pitch 37x37 num-electrodes 8x7 
> > > > > physical size 25x22mm res 69x69 max 1792x1536
> > > > > 
> > > > > Let me know if you have any further test.
> > > > > 
> > > > > 
> > > > > thanks,
> > > > > 
> > > > > Takashi
> > > > 
> > > > Do you have the kernel output from the second patch?
> > > 
> > > Here it is:
> > > 
> > > psmouse serio1: alps: test2 pitch 50x54 num-electrodes 20x11 
> > > physical size 95x54mm res 25x23 max 2432x1280
> > 
> > Thanks!
> > 
> > Wow, this is weird ... Values that cause scrolling issues for you work fine for me.
> > 
> > It looks like the priv->x_max value that is causing your problem, but perhaps you can confirm this with another test:
> > Revert the patches above, then just before the 'return' at the end of alps_update_device_area_ss4_v2() add the following line:
> > priv->x_max = 1792;
> > I suspect this line will make two-finger scrolling work again.
> > 
> > It might also help if you could experiment with other x_max values.  2432 is the correct value that causes problems for you..  Does a small value like 500 or a large value like 5000 change the behavior?
> > 
> > Another test you can try is to add a print statement in the 'case SS4_PACKET_ID_TWO' section of alps_decode_ss4_v2() and print out the f->mt[0].x and f->mt[1].x values.  With x_max set to 2432, what range of x values does this print when scrolling works, and what range of values are printed when scrolling doesn't work?
> 
> Sorry for the late reply.
> 
> I checked your suggestion, and noticed that actually x_max is a red herring.  Then I started looking at the output of evtest (should have done from the beginning!), and the problem became obvious: the reported X values for MT with finger > 1 are doubled, e.g. it reports
> 4800 instead of 2400.  The MT_Y coordinate looks OK, so it's only about MT_X.  And finger=1 reports correctly.
> 
> After reading the code, I ended up the patch like below.  This seems working through a quick test.  Could anyone check the patch to see whether it works / breaks anything?
> 
> The evtest showed that the MT_X for finger 3 and 4 are also bogus, and the patch should address it, too.
> 
> My only concern so far is whether correcting this globally is right, or it's specific to some certain models.  This needs the confirmation from ALPS people...
> 
> 
> thanks,
> 
> Takashi
> 
> 
> --- a/drivers/input/mouse/alps.h
> +++ b/drivers/input/mouse/alps.h
> @@ -96,8 +96,8 @@ enum SS4_PACKET_ID {
>  
>  #define SS4_BTN_V2(_b)		((_b[0] >> 5) & SS4_MASK_NORMAL_BUTTONS)
>  
> -#define SS4_STD_MF_X_V2(_b, _i)	(((_b[0 + (_i) * 3] << 5) & 0x00E0) |	\
> -				 ((_b[1 + _i * 3]  << 5) & 0x1F00)	\
> +#define SS4_STD_MF_X_V2(_b, _i)	(((_b[0 + (_i) * 3] << 4) & 0x0070) |	\
> +				 ((_b[1 + (_i) * 3] << 4) & 0x0F80)	\
>  				)
>  
>  #define SS4_STD_MF_Y_V2(_b, _i)	(((_b[1 + (_i) * 3] << 3) & 0x0010) |	\
> @@ -106,7 +106,7 @@ enum SS4_PACKET_ID {
>  				)
>  
>  #define SS4_BTL_MF_X_V2(_b, _i)	(SS4_STD_MF_X_V2(_b, _i) |		\
> -				 ((_b[0 + (_i) * 3] >> 3) & 0x0010)	\
> +				 ((_b[0 + (_i) * 3] >> 2) & 0x0008)	\
>  				)
>  
>  #define SS4_BTL_MF_Y_V2(_b, _i)	(SS4_STD_MF_Y_V2(_b, _i) | \
>