diff mbox

[2/3] Input: tsc2007 - correctly report pressure and not resistance to user space

Message ID 9e249276be9e20aab1a74617373bf6587f1acd4b.1487609795.git.hns@goldelico.com (mailing list archive)
State Accepted
Headers show

Commit Message

H. Nikolaus Schaller Feb. 20, 2017, 4:56 p.m. UTC
previously, tsc2007 will report as ABS_PRESSURE:
0              for no pressure (resistance infinite)
high value     for soft pressure (high resistance)
low value      for firm pressure (lower resistance)

This does not matter for most applications (e.g. GUI, Menu, Scrolling
etc.) where the ABS_PRESSURE is ignored and only BTN_TOUCH is processed
to detect screen taps.

Only some special graphics applications read the pressure channel and
they will be mixed up by this non-monotonic relation.

So we fix it to become:
0              for no pressure (resistance infinite)
low value      for soft pressure (high resistance)
high value     for firm pressure (lower resistance)

While this patch changes the values reported to userspace,
ABS_PRESSURE is used rarely by userspace. Most software only
relies on BTN_TOUCH (boolean), which is not affected by this
patch. Some graphics software makes use of the interface and
does not work correctly with the currently used inverted
behaviour.

Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
---
 drivers/input/touchscreen/tsc2007_core.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Sebastian Reichel Feb. 21, 2017, 5:13 p.m. UTC | #1
Hi,

On Mon, Feb 20, 2017 at 05:56:35PM +0100, H. Nikolaus Schaller wrote:
> previously, tsc2007 will report as ABS_PRESSURE:
> 0              for no pressure (resistance infinite)
> high value     for soft pressure (high resistance)
> low value      for firm pressure (lower resistance)
> 
> This does not matter for most applications (e.g. GUI, Menu, Scrolling
> etc.) where the ABS_PRESSURE is ignored and only BTN_TOUCH is processed
> to detect screen taps.
> 
> Only some special graphics applications read the pressure channel and
> they will be mixed up by this non-monotonic relation.
> 
> So we fix it to become:
> 0              for no pressure (resistance infinite)
> low value      for soft pressure (high resistance)
> high value     for firm pressure (lower resistance)
> 
> While this patch changes the values reported to userspace,
> ABS_PRESSURE is used rarely by userspace. Most software only
> relies on BTN_TOUCH (boolean), which is not affected by this
> patch. Some graphics software makes use of the interface and
> does not work correctly with the currently used inverted
> behaviour.
> 
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> ---
>  drivers/input/touchscreen/tsc2007_core.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/input/touchscreen/tsc2007_core.c b/drivers/input/touchscreen/tsc2007_core.c
> index 30b53ca..fc73849 100644
> --- a/drivers/input/touchscreen/tsc2007_core.c
> +++ b/drivers/input/touchscreen/tsc2007_core.c
> @@ -141,6 +141,8 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
>  				"DOWN point(%4d,%4d), resistance (%4u)\n",
>  				tc.x, tc.y, rt);
>  
> +			rt = ts->max_rt - rt;
> +
>  			input_report_key(input, BTN_TOUCH, 1);
>  			input_report_abs(input, ABS_X, tc.x);
>  			input_report_abs(input, ABS_Y, tc.y);

Reviewed-By: Sebastian Reichel <sre@kernel.org>

We should add the same to ts200x-core.

-- Sebastian
Dmitry Torokhov Feb. 23, 2017, 8:45 a.m. UTC | #2
On Tue, Feb 21, 2017 at 06:13:32PM +0100, Sebastian Reichel wrote:
> Hi,
> 
> On Mon, Feb 20, 2017 at 05:56:35PM +0100, H. Nikolaus Schaller wrote:
> > previously, tsc2007 will report as ABS_PRESSURE:
> > 0              for no pressure (resistance infinite)
> > high value     for soft pressure (high resistance)
> > low value      for firm pressure (lower resistance)
> > 
> > This does not matter for most applications (e.g. GUI, Menu, Scrolling
> > etc.) where the ABS_PRESSURE is ignored and only BTN_TOUCH is processed
> > to detect screen taps.
> > 
> > Only some special graphics applications read the pressure channel and
> > they will be mixed up by this non-monotonic relation.
> > 
> > So we fix it to become:
> > 0              for no pressure (resistance infinite)
> > low value      for soft pressure (high resistance)
> > high value     for firm pressure (lower resistance)
> > 
> > While this patch changes the values reported to userspace,
> > ABS_PRESSURE is used rarely by userspace. Most software only
> > relies on BTN_TOUCH (boolean), which is not affected by this
> > patch. Some graphics software makes use of the interface and
> > does not work correctly with the currently used inverted
> > behaviour.
> > 
> > Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> > ---
> >  drivers/input/touchscreen/tsc2007_core.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/input/touchscreen/tsc2007_core.c b/drivers/input/touchscreen/tsc2007_core.c
> > index 30b53ca..fc73849 100644
> > --- a/drivers/input/touchscreen/tsc2007_core.c
> > +++ b/drivers/input/touchscreen/tsc2007_core.c
> > @@ -141,6 +141,8 @@ static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
> >  				"DOWN point(%4d,%4d), resistance (%4u)\n",
> >  				tc.x, tc.y, rt);
> >  
> > +			rt = ts->max_rt - rt;
> > +
> >  			input_report_key(input, BTN_TOUCH, 1);
> >  			input_report_abs(input, ABS_X, tc.x);
> >  			input_report_abs(input, ABS_Y, tc.y);
> 
> Reviewed-By: Sebastian Reichel <sre@kernel.org>

Applied, thank you.
diff mbox

Patch

diff --git a/drivers/input/touchscreen/tsc2007_core.c b/drivers/input/touchscreen/tsc2007_core.c
index 30b53ca..fc73849 100644
--- a/drivers/input/touchscreen/tsc2007_core.c
+++ b/drivers/input/touchscreen/tsc2007_core.c
@@ -141,6 +141,8 @@  static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 				"DOWN point(%4d,%4d), resistance (%4u)\n",
 				tc.x, tc.y, rt);
 
+			rt = ts->max_rt - rt;
+
 			input_report_key(input, BTN_TOUCH, 1);
 			input_report_abs(input, ABS_X, tc.x);
 			input_report_abs(input, ABS_Y, tc.y);