On Sat, Nov 27, 2010 at 03:39:02PM -0800, Dmitry Torokhov wrote:
> On Sat, Nov 27, 2010 at 12:46:03PM +0300, Nikolai Kondrashov wrote:
> > On 11/27/2010 12:15 PM, Dmitry Torokhov wrote:
> > >2000LPI == about 79 l/mm. How is it not useable?
> > TBH, I didn't make any real calculations.
> > The introduced error isn't very high, indeed. The vertical size of 4x3 inch
> > tablet becomes 75 mm instead of 76 mm. So maybe it's alright.
> >
> > >In mainline synaptics is the only one that does this. We do not know how
> > >many drivers in vendor trees fill and use this data nor we do not know
> > >about userspace. The fact that we were not able to locate them does not
> > >mean they do not exist. The units/mm are part of input ABI now.
> > Well, I can't argue with you here.
> > I didn't think about 3rd party drivers, TBH.
> >
> > >Right, standarize on existing UOM (which are per/mm) and then implement
> > >other UOM if theya re really needed.
> > Will this fix qualify for inclusion into 2.6.37?
>
> Yes, I believe it does.
>
Does the following work by any chance?
Thanks.
--
Dmitry
HID: length resolution should be reported units/mm
From: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Input ABI requires reporting resolution on main axes in units per
millimeter, not units per inch, so we need to convert accordingly.
Signed-off-by: Dmitry Torokhov <dtor@xxxxxxx>
---
drivers/hid/hid-input.c | 19 +++++++++++--------
1 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index c9c90de..5cde845 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -203,8 +203,8 @@ static int hidinput_setkeycode(struct input_dev *dev,
*
* as seen in the HID specification v1.11 6.2.2.7 Global Items.
*
- * Only exponent 1 length units are processed. Centimeters are converted to
- * inches. Degrees are converted to radians.
+ * Only exponent 1 length units are processed. Centimeters and inches are
+ * converted to millimeters. Degrees are converted to radians.
*/
static __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
{
@@ -225,13 +225,16 @@ static __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
*/
if (code == ABS_X || code == ABS_Y || code == ABS_Z) {
if (field->unit == 0x11) { /* If centimeters */
- /* Convert to inches */
- prev = logical_extents;
- logical_extents *= 254;
- if (logical_extents < prev)
+ /* Convert to millimeters */
+ unit_exponent += 1;
+ } else if (field->unit == 0x13) { /* If inches */
+ /* Convert to millimeters */
+ prev = physical_extents;
+ physical_extents *= 254;
+ if (physical_extents < prev)
return 0;
- unit_exponent += 2;
- } else if (field->unit != 0x13) { /* If not inches */
+ unit_exponent -= 1;
+ } else {
return 0;
}
} else if (code == ABS_RX || code == ABS_RY || code == ABS_RZ) {
--
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