2 files changed, 10 insertions, 14 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 5a8c01112a23..a9ca93c1192c 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -319,7 +319,7 @@ static s32 item_sdata(struct hid_item *item)
 
 static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
 {
-        __u32 raw_value;
+        __s32 raw_value;
         switch (item->tag) {
         case HID_GLOBAL_ITEM_TAG_PUSH:
 
@@ -370,10 +370,11 @@ static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
                 return 0;
 
         case HID_GLOBAL_ITEM_TAG_UNIT_EXPONENT:
-                /* Units exponent negative numbers are given through a
-                 * two's complement.
-                 * See "6.2.2.7 Global Items" for more information. */
-                raw_value = item_udata(item);
+                /* Many devices provide unit exponent as a two's complement
+                 * nibble due to the common misunderstanding of HID
+                 * specification 1.11, 6.2.2.7 Global Items. Attempt to handle
+                 * both this and the standard encoding. */
+                raw_value = item_sdata(item);
                 if (!(raw_value & 0xfffffff0))
                         parser->global.unit_exponent = hid_snto32(raw_value, 4);
                 else
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 8741d953dcc8..d97f2323af57 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -192,6 +192,7 @@ static int hidinput_setkeycode(struct input_dev *dev,
         return -EINVAL;
 }
 
+
 /**
  * hidinput_calc_abs_res - calculate an absolute axis resolution
  * @field: the HID report field to calculate resolution for
@@ -234,23 +235,17 @@ __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code)
         case ABS_MT_TOOL_Y:
         case ABS_MT_TOUCH_MAJOR:
         case ABS_MT_TOUCH_MINOR:
-                if (field->unit & 0xffffff00)           /* Not a length */
-                        return 0;
-                unit_exponent += hid_snto32(field->unit >> 4, 4) - 1;
-                switch (field->unit & 0xf) {
-                case 0x1:                               /* If centimeters */
+                if (field->unit == 0x11) {              /* If centimeters */
                         /* Convert to millimeters */
                         unit_exponent += 1;
-                        break;
-                case 0x3:                               /* If inches */
+                } else if (field->unit == 0x13) {       /* If inches */
                         /* Convert to millimeters */
                         prev = physical_extents;
                         physical_extents *= 254;
                         if (physical_extents < prev)
                                 return 0;
                         unit_exponent -= 1;
-                        break;
-                default:
+                } else {
                         return 0;
                 }
                 break;