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

[Paul Donohue <linux-kernel@PaulSD.com>]

On Tue, Jul 11, 2017 at 05:50:07PM +0200, Takashi Iwai wrote:
> On Tue, 20 Jun 2017 01:20:26 +0200,
> Paul Donohue wrote:
> > 
> > On Mon, Jun 19, 2017 at 01:02:18PM -0700, Laura Abbott wrote:
> > > On 06/19/2017 11:43 AM, Paul Donohue wrote:
> > > > I get the same results as you - x_max and y_max affect cursor speed, and x_res and y_res seem to have no effect.  I can't seem to come up with any values that cause intermittent cursor issues on one side of the touchpad.
> > > > Both max and res do get passed up to the X driver, and I do see references to both max and resolution in xf86-input-evdev, although I haven't actually traced it through to see if/where each value is actually consumed with my setup.
> > > > 
> > > > Maybe we should ask the user to try a few more tests?
> > > > 1) Using the original code (without the modifications from bug 195215), add the following before 'return 0' at the end of alps_update_device_area_ss4_v2(), then run `dmesg | grep num-electrodes` after loading the alps kernel module to get the output.  This should tell us what values the user is actually reading from the hardware:
> > > > psmouse_err(psmouse,
> > > >     "pitch %dx%d num-electrodes %dx%d physical size %dx%dmm res %dx%d max %dx%d\n",
> > > >     x_pitch, y_pitch, num_x_electrode, num_y_electrode,
> > > >     x_phys / 10, y_phys / 10, priv->x_res, priv->y_res, priv->x_max, priv->y_max);
> > > > 2) Use the old electrode count code but the new pitch code:
> > > > 	if (IS_SS4PLUS_DEV(priv->dev_id)) {
> > > > 		num_x_electrode =
> > > > 			SS4_NUMSENSOR_XOFFSET + (otp[1][0] & 0x0F);
> > > > 		num_y_electrode =
> > > > 			SS4_NUMSENSOR_YOFFSET + ((otp[1][0] >> 4) & 0x0F);
> > > > 
> > > > 		priv->x_max =
> > > > 			(num_x_electrode - 1) * SS4_COUNT_PER_ELECTRODE;
> > > > 		priv->y_max =
> > > > 			(num_y_electrode - 1) * SS4_COUNT_PER_ELECTRODE;
> > > > 
> > > > 		x_pitch = (otp[0][1] & 0x0F) + SS4PLUS_MIN_PITCH_MM;
> > > > 		y_pitch = ((otp[0][1] >> 4) & 0x0F) + SS4PLUS_MIN_PITCH_MM;
> > > > 
> > > > 	} else {
> > > > 3) Use the new electrode count code but the old pitch code:
> > > > 	if (IS_SS4PLUS_DEV(priv->dev_id)) {
> > > > 		num_x_electrode =
> > > > 			SS4PLUS_NUMSENSOR_XOFFSET + (otp[0][2] & 0x0F);
> > > > 		num_y_electrode =
> > > > 			SS4PLUS_NUMSENSOR_YOFFSET + ((otp[0][2] >> 4) & 0x0F);
> > > > 
> > > > 		priv->x_max =
> > > > 			(num_x_electrode - 1) * SS4PLUS_COUNT_PER_ELECTRODE;
> > > > 		priv->y_max =
> > > > 			(num_y_electrode - 1) * SS4PLUS_COUNT_PER_ELECTRODE;
> > > > 
> > > > 		x_pitch = ((otp[1][2] >> 2) & 0x07) + SS4_MIN_PITCH_MM;
> > > > 		y_pitch = ((otp[1][2] >> 5) & 0x07) + SS4_MIN_PITCH_MM;
> > > > 
> > > > 	} else {
> > > > 
> > > 
> > > Can you produce patches for these test cases?
> > 
> > I've reduced it to two test cases.  Patches attached.
> 
> 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?

Thanks!
-Paul