diff mbox series

HID: kye: Change Device Usage from Puck to Mouse

Message ID 20240502042335.15611-1-mmyangfl@gmail.com (mailing list archive)
State Mainlined
Commit f273cbf831d4359b602980a36e3d0c02a16104f9
Delegated to: Jiri Kosina
Headers show
Series HID: kye: Change Device Usage from Puck to Mouse | expand

Commit Message

David Yang May 2, 2024, 4:23 a.m. UTC
Change device type because
a. it is exactly a mouse, with left/right buttons and scroll wheel;
b. it does not have visible marks or crosshairs, thus does not provide
higher accuracy than stylus.

Signed-off-by: David Yang <mmyangfl@gmail.com>
---
 drivers/hid/hid-kye.c | 75 +++++++++++++++++++++++++------------------
 1 file changed, 44 insertions(+), 31 deletions(-)

Comments

Jiri Kosina May 6, 2024, 9:30 p.m. UTC | #1
On Thu, 2 May 2024, David Yang wrote:

> Change device type because
> a. it is exactly a mouse, with left/right buttons and scroll wheel;
> b. it does not have visible marks or crosshairs, thus does not provide
> higher accuracy than stylus.

Let's CC Milan, who originally added all this in feb6faf1e5d46 ("HID: kye: 
Fix report descriptor for Genius PenSketch M912") ... Milan, any concerns 
about the below?

Thanks.

> 
> Signed-off-by: David Yang <mmyangfl@gmail.com>
> ---
>  drivers/hid/hid-kye.c | 75 +++++++++++++++++++++++++------------------
>  1 file changed, 44 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/hid/hid-kye.c b/drivers/hid/hid-kye.c
> index eb9bf2829937..70ceb9437332 100644
> --- a/drivers/hid/hid-kye.c
> +++ b/drivers/hid/hid-kye.c
> @@ -209,7 +209,7 @@ static const __u8 pensketch_t609a_control_rdesc[] = {
>  	0xC0               /*  End Collection            */
>  };
>  
> -/* Fix indexes in kye_tablet_fixup if you change this */
> +/* Fix indexes in kye_tablet_fixup() if you change this */
>  static const __u8 kye_tablet_rdesc[] = {
>  	0x06, 0x00, 0xFF,             /*  Usage Page (FF00h),             */
>  	0x09, 0x01,                   /*  Usage (01h),                    */
> @@ -262,12 +262,16 @@ static const __u8 kye_tablet_rdesc[] = {
>  	0x27, 0xFF, 0x07, 0x00, 0x00, /*      Logical Maximum (2047),     */
>  	0x81, 0x02,                   /*      Input (Variable),           */
>  	0xC0,                         /*    End Collection,               */
> -	0xC0,                         /*  End Collection,                 */
> -	0x05, 0x0D,                   /*  Usage Page (Digitizer),         */
> -	0x09, 0x21,                   /*  Usage (Puck),                   */
> +	0xC0                          /*  End Collection,                 */
> +};
> +
> +/* Fix indexes in kye_tablet_fixup() if you change this */
> +static const __u8 kye_tablet_mouse_rdesc[] = {
> +	0x05, 0x01,                   /*  Usage Page (Desktop),           */
> +	0x09, 0x02,                   /*  Usage (Mouse),                  */
>  	0xA1, 0x01,                   /*  Collection (Application),       */
>  	0x85, 0x11,                   /*    Report ID (17),               */
> -	0x09, 0x21,                   /*    Usage (Puck),                 */
> +	0x09, 0x01,                   /*    Usage (Pointer),              */
>  	0xA0,                         /*    Collection (Physical),        */
>  	0x05, 0x09,                   /*      Usage Page (Button),        */
>  	0x19, 0x01,                   /*      Usage Minimum (01h),        */
> @@ -280,7 +284,7 @@ static const __u8 kye_tablet_rdesc[] = {
>  	0x95, 0x04,                   /*      Report Count (4),           */
>  	0x81, 0x01,                   /*      Input (Constant),           */
>  	0x05, 0x0D,                   /*      Usage Page (Digitizer),     */
> -	0x09, 0x32,                   /*      Usage (In Range),           */
> +	0x09, 0x37,                   /*      Usage (Data Valid),         */
>  	0x95, 0x01,                   /*      Report Count (1),           */
>  	0x81, 0x02,                   /*      Input (Variable),           */
>  	0x05, 0x01,                   /*      Usage Page (Desktop),       */
> @@ -317,7 +321,7 @@ static const struct kye_tablet_info {
>  	__s32 y_physical_maximum;
>  	__s8 unit_exponent;
>  	__s8 unit;
> -	bool has_punk;
> +	bool has_mouse;
>  	unsigned int control_rsize;
>  	const __u8 *control_rdesc;
>  } kye_tablets_info[] = {
> @@ -402,7 +406,7 @@ static __u8 *kye_consumer_control_fixup(struct hid_device *hdev, __u8 *rdesc,
>  static __u8 *kye_tablet_fixup(struct hid_device *hdev, __u8 *rdesc, unsigned int *rsize)
>  {
>  	const struct kye_tablet_info *info;
> -	unsigned int newsize;
> +	__u8 *newdesc = rdesc;
>  
>  	if (*rsize < sizeof(kye_tablet_rdesc)) {
>  		hid_warn(hdev,
> @@ -420,36 +424,45 @@ static __u8 *kye_tablet_fixup(struct hid_device *hdev, __u8 *rdesc, unsigned int
>  		return rdesc;
>  	}
>  
> -	newsize = info->has_punk ? sizeof(kye_tablet_rdesc) : 112;
> -	memcpy(rdesc, kye_tablet_rdesc, newsize);
> -
> -	put_unaligned_le32(info->x_logical_maximum, rdesc + 66);
> -	put_unaligned_le32(info->x_physical_maximum, rdesc + 72);
> -	rdesc[77] = info->unit;
> -	rdesc[79] = info->unit_exponent;
> -	put_unaligned_le32(info->y_logical_maximum, rdesc + 87);
> -	put_unaligned_le32(info->y_physical_maximum, rdesc + 92);
> -	put_unaligned_le32(info->pressure_logical_maximum, rdesc + 104);
> -
> -	if (info->has_punk) {
> -		put_unaligned_le32(info->x_logical_maximum, rdesc + 156);
> -		put_unaligned_le32(info->x_physical_maximum, rdesc + 162);
> -		rdesc[167] = info->unit;
> -		rdesc[169] = info->unit_exponent;
> -		put_unaligned_le32(info->y_logical_maximum, rdesc + 177);
> -		put_unaligned_le32(info->y_physical_maximum, rdesc + 182);
> +	memcpy(newdesc, kye_tablet_rdesc, sizeof(kye_tablet_rdesc));
> +
> +	put_unaligned_le32(info->x_logical_maximum, newdesc + 66);
> +	put_unaligned_le32(info->x_physical_maximum, newdesc + 72);
> +	newdesc[77] = info->unit;
> +	newdesc[79] = info->unit_exponent;
> +	put_unaligned_le32(info->y_logical_maximum, newdesc + 87);
> +	put_unaligned_le32(info->y_physical_maximum, newdesc + 92);
> +	put_unaligned_le32(info->pressure_logical_maximum, newdesc + 104);
> +
> +	newdesc += sizeof(kye_tablet_rdesc);
> +
> +	if (info->has_mouse) {
> +		if (newdesc + sizeof(kye_tablet_mouse_rdesc) > rdesc + *rsize)
> +			hid_err(hdev, "control desc unexpectedly large\n");
> +		else {
> +			memcpy(newdesc, kye_tablet_mouse_rdesc, sizeof(kye_tablet_mouse_rdesc));
> +
> +			put_unaligned_le32(info->x_logical_maximum, newdesc + 44);
> +			put_unaligned_le32(info->x_physical_maximum, newdesc + 50);
> +			newdesc[55] = info->unit;
> +			newdesc[57] = info->unit_exponent;
> +			put_unaligned_le32(info->y_logical_maximum, newdesc + 65);
> +			put_unaligned_le32(info->y_physical_maximum, newdesc + 70);
> +
> +			newdesc += sizeof(kye_tablet_mouse_rdesc);
> +		}
>  	}
>  
>  	if (info->control_rsize) {
> -		if (newsize + info->control_rsize > *rsize)
> -			hid_err(hdev, "control rdesc unexpectedly large");
> +		if (newdesc + info->control_rsize > rdesc + *rsize)
> +			hid_err(hdev, "control desc unexpectedly large\n");
>  		else {
> -			memcpy(rdesc + newsize, info->control_rdesc, info->control_rsize);
> -			newsize += info->control_rsize;
> +			memcpy(newdesc, info->control_rdesc, info->control_rsize);
> +			newdesc += info->control_rsize;
>  		}
>  	}
>  
> -	*rsize = newsize;
> +	*rsize = newdesc - rdesc;
>  	return rdesc;
>  }
>  
> -- 
> 2.43.0
>
Milan Plžík May 7, 2024, 12:29 p.m. UTC | #2
Hello Jiri, David,

no objections here. Unfortunately, I can't test the change at the
moment (I barely remember there was a mouse that could be used with
that tablet), but the change sounds good to me. Also, thanks a lot for
keeping the HID drivers up-to-date even for such old hardware :)

Best,
  Milan


On Mon, May 6, 2024 at 11:30 PM Jiri Kosina <jikos@kernel.org> wrote:
>
> On Thu, 2 May 2024, David Yang wrote:
>
> > Change device type because
> > a. it is exactly a mouse, with left/right buttons and scroll wheel;
> > b. it does not have visible marks or crosshairs, thus does not provide
> > higher accuracy than stylus.
>
> Let's CC Milan, who originally added all this in feb6faf1e5d46 ("HID: kye:
> Fix report descriptor for Genius PenSketch M912") ... Milan, any concerns
> about the below?
>
> Thanks.
>
> >
> > Signed-off-by: David Yang <mmyangfl@gmail.com>
> > ---
> >  drivers/hid/hid-kye.c | 75 +++++++++++++++++++++++++------------------
> >  1 file changed, 44 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/hid/hid-kye.c b/drivers/hid/hid-kye.c
> > index eb9bf2829937..70ceb9437332 100644
> > --- a/drivers/hid/hid-kye.c
> > +++ b/drivers/hid/hid-kye.c
> > @@ -209,7 +209,7 @@ static const __u8 pensketch_t609a_control_rdesc[] = {
> >       0xC0               /*  End Collection            */
> >  };
> >
> > -/* Fix indexes in kye_tablet_fixup if you change this */
> > +/* Fix indexes in kye_tablet_fixup() if you change this */
> >  static const __u8 kye_tablet_rdesc[] = {
> >       0x06, 0x00, 0xFF,             /*  Usage Page (FF00h),             */
> >       0x09, 0x01,                   /*  Usage (01h),                    */
> > @@ -262,12 +262,16 @@ static const __u8 kye_tablet_rdesc[] = {
> >       0x27, 0xFF, 0x07, 0x00, 0x00, /*      Logical Maximum (2047),     */
> >       0x81, 0x02,                   /*      Input (Variable),           */
> >       0xC0,                         /*    End Collection,               */
> > -     0xC0,                         /*  End Collection,                 */
> > -     0x05, 0x0D,                   /*  Usage Page (Digitizer),         */
> > -     0x09, 0x21,                   /*  Usage (Puck),                   */
> > +     0xC0                          /*  End Collection,                 */
> > +};
> > +
> > +/* Fix indexes in kye_tablet_fixup() if you change this */
> > +static const __u8 kye_tablet_mouse_rdesc[] = {
> > +     0x05, 0x01,                   /*  Usage Page (Desktop),           */
> > +     0x09, 0x02,                   /*  Usage (Mouse),                  */
> >       0xA1, 0x01,                   /*  Collection (Application),       */
> >       0x85, 0x11,                   /*    Report ID (17),               */
> > -     0x09, 0x21,                   /*    Usage (Puck),                 */
> > +     0x09, 0x01,                   /*    Usage (Pointer),              */
> >       0xA0,                         /*    Collection (Physical),        */
> >       0x05, 0x09,                   /*      Usage Page (Button),        */
> >       0x19, 0x01,                   /*      Usage Minimum (01h),        */
> > @@ -280,7 +284,7 @@ static const __u8 kye_tablet_rdesc[] = {
> >       0x95, 0x04,                   /*      Report Count (4),           */
> >       0x81, 0x01,                   /*      Input (Constant),           */
> >       0x05, 0x0D,                   /*      Usage Page (Digitizer),     */
> > -     0x09, 0x32,                   /*      Usage (In Range),           */
> > +     0x09, 0x37,                   /*      Usage (Data Valid),         */
> >       0x95, 0x01,                   /*      Report Count (1),           */
> >       0x81, 0x02,                   /*      Input (Variable),           */
> >       0x05, 0x01,                   /*      Usage Page (Desktop),       */
> > @@ -317,7 +321,7 @@ static const struct kye_tablet_info {
> >       __s32 y_physical_maximum;
> >       __s8 unit_exponent;
> >       __s8 unit;
> > -     bool has_punk;
> > +     bool has_mouse;
> >       unsigned int control_rsize;
> >       const __u8 *control_rdesc;
> >  } kye_tablets_info[] = {
> > @@ -402,7 +406,7 @@ static __u8 *kye_consumer_control_fixup(struct hid_device *hdev, __u8 *rdesc,
> >  static __u8 *kye_tablet_fixup(struct hid_device *hdev, __u8 *rdesc, unsigned int *rsize)
> >  {
> >       const struct kye_tablet_info *info;
> > -     unsigned int newsize;
> > +     __u8 *newdesc = rdesc;
> >
> >       if (*rsize < sizeof(kye_tablet_rdesc)) {
> >               hid_warn(hdev,
> > @@ -420,36 +424,45 @@ static __u8 *kye_tablet_fixup(struct hid_device *hdev, __u8 *rdesc, unsigned int
> >               return rdesc;
> >       }
> >
> > -     newsize = info->has_punk ? sizeof(kye_tablet_rdesc) : 112;
> > -     memcpy(rdesc, kye_tablet_rdesc, newsize);
> > -
> > -     put_unaligned_le32(info->x_logical_maximum, rdesc + 66);
> > -     put_unaligned_le32(info->x_physical_maximum, rdesc + 72);
> > -     rdesc[77] = info->unit;
> > -     rdesc[79] = info->unit_exponent;
> > -     put_unaligned_le32(info->y_logical_maximum, rdesc + 87);
> > -     put_unaligned_le32(info->y_physical_maximum, rdesc + 92);
> > -     put_unaligned_le32(info->pressure_logical_maximum, rdesc + 104);
> > -
> > -     if (info->has_punk) {
> > -             put_unaligned_le32(info->x_logical_maximum, rdesc + 156);
> > -             put_unaligned_le32(info->x_physical_maximum, rdesc + 162);
> > -             rdesc[167] = info->unit;
> > -             rdesc[169] = info->unit_exponent;
> > -             put_unaligned_le32(info->y_logical_maximum, rdesc + 177);
> > -             put_unaligned_le32(info->y_physical_maximum, rdesc + 182);
> > +     memcpy(newdesc, kye_tablet_rdesc, sizeof(kye_tablet_rdesc));
> > +
> > +     put_unaligned_le32(info->x_logical_maximum, newdesc + 66);
> > +     put_unaligned_le32(info->x_physical_maximum, newdesc + 72);
> > +     newdesc[77] = info->unit;
> > +     newdesc[79] = info->unit_exponent;
> > +     put_unaligned_le32(info->y_logical_maximum, newdesc + 87);
> > +     put_unaligned_le32(info->y_physical_maximum, newdesc + 92);
> > +     put_unaligned_le32(info->pressure_logical_maximum, newdesc + 104);
> > +
> > +     newdesc += sizeof(kye_tablet_rdesc);
> > +
> > +     if (info->has_mouse) {
> > +             if (newdesc + sizeof(kye_tablet_mouse_rdesc) > rdesc + *rsize)
> > +                     hid_err(hdev, "control desc unexpectedly large\n");
> > +             else {
> > +                     memcpy(newdesc, kye_tablet_mouse_rdesc, sizeof(kye_tablet_mouse_rdesc));
> > +
> > +                     put_unaligned_le32(info->x_logical_maximum, newdesc + 44);
> > +                     put_unaligned_le32(info->x_physical_maximum, newdesc + 50);
> > +                     newdesc[55] = info->unit;
> > +                     newdesc[57] = info->unit_exponent;
> > +                     put_unaligned_le32(info->y_logical_maximum, newdesc + 65);
> > +                     put_unaligned_le32(info->y_physical_maximum, newdesc + 70);
> > +
> > +                     newdesc += sizeof(kye_tablet_mouse_rdesc);
> > +             }
> >       }
> >
> >       if (info->control_rsize) {
> > -             if (newsize + info->control_rsize > *rsize)
> > -                     hid_err(hdev, "control rdesc unexpectedly large");
> > +             if (newdesc + info->control_rsize > rdesc + *rsize)
> > +                     hid_err(hdev, "control desc unexpectedly large\n");
> >               else {
> > -                     memcpy(rdesc + newsize, info->control_rdesc, info->control_rsize);
> > -                     newsize += info->control_rsize;
> > +                     memcpy(newdesc, info->control_rdesc, info->control_rsize);
> > +                     newdesc += info->control_rsize;
> >               }
> >       }
> >
> > -     *rsize = newsize;
> > +     *rsize = newdesc - rdesc;
> >       return rdesc;
> >  }
> >
> > --
> > 2.43.0
> >
>
> --
> Jiri Kosina
> SUSE Labs
>
Jiri Kosina May 7, 2024, 1:18 p.m. UTC | #3
On Tue, 7 May 2024, Milan Plžík wrote:

> no objections here. Unfortunately, I can't test the change at the moment 
> (I barely remember there was a mouse that could be used with that 
> tablet), but the change sounds good to me. Also, thanks a lot for 
> keeping the HID drivers up-to-date even for such old hardware :)

Thanks for the prompt response. I've applied David's patch now.
diff mbox series

Patch

diff --git a/drivers/hid/hid-kye.c b/drivers/hid/hid-kye.c
index eb9bf2829937..70ceb9437332 100644
--- a/drivers/hid/hid-kye.c
+++ b/drivers/hid/hid-kye.c
@@ -209,7 +209,7 @@  static const __u8 pensketch_t609a_control_rdesc[] = {
 	0xC0               /*  End Collection            */
 };
 
-/* Fix indexes in kye_tablet_fixup if you change this */
+/* Fix indexes in kye_tablet_fixup() if you change this */
 static const __u8 kye_tablet_rdesc[] = {
 	0x06, 0x00, 0xFF,             /*  Usage Page (FF00h),             */
 	0x09, 0x01,                   /*  Usage (01h),                    */
@@ -262,12 +262,16 @@  static const __u8 kye_tablet_rdesc[] = {
 	0x27, 0xFF, 0x07, 0x00, 0x00, /*      Logical Maximum (2047),     */
 	0x81, 0x02,                   /*      Input (Variable),           */
 	0xC0,                         /*    End Collection,               */
-	0xC0,                         /*  End Collection,                 */
-	0x05, 0x0D,                   /*  Usage Page (Digitizer),         */
-	0x09, 0x21,                   /*  Usage (Puck),                   */
+	0xC0                          /*  End Collection,                 */
+};
+
+/* Fix indexes in kye_tablet_fixup() if you change this */
+static const __u8 kye_tablet_mouse_rdesc[] = {
+	0x05, 0x01,                   /*  Usage Page (Desktop),           */
+	0x09, 0x02,                   /*  Usage (Mouse),                  */
 	0xA1, 0x01,                   /*  Collection (Application),       */
 	0x85, 0x11,                   /*    Report ID (17),               */
-	0x09, 0x21,                   /*    Usage (Puck),                 */
+	0x09, 0x01,                   /*    Usage (Pointer),              */
 	0xA0,                         /*    Collection (Physical),        */
 	0x05, 0x09,                   /*      Usage Page (Button),        */
 	0x19, 0x01,                   /*      Usage Minimum (01h),        */
@@ -280,7 +284,7 @@  static const __u8 kye_tablet_rdesc[] = {
 	0x95, 0x04,                   /*      Report Count (4),           */
 	0x81, 0x01,                   /*      Input (Constant),           */
 	0x05, 0x0D,                   /*      Usage Page (Digitizer),     */
-	0x09, 0x32,                   /*      Usage (In Range),           */
+	0x09, 0x37,                   /*      Usage (Data Valid),         */
 	0x95, 0x01,                   /*      Report Count (1),           */
 	0x81, 0x02,                   /*      Input (Variable),           */
 	0x05, 0x01,                   /*      Usage Page (Desktop),       */
@@ -317,7 +321,7 @@  static const struct kye_tablet_info {
 	__s32 y_physical_maximum;
 	__s8 unit_exponent;
 	__s8 unit;
-	bool has_punk;
+	bool has_mouse;
 	unsigned int control_rsize;
 	const __u8 *control_rdesc;
 } kye_tablets_info[] = {
@@ -402,7 +406,7 @@  static __u8 *kye_consumer_control_fixup(struct hid_device *hdev, __u8 *rdesc,
 static __u8 *kye_tablet_fixup(struct hid_device *hdev, __u8 *rdesc, unsigned int *rsize)
 {
 	const struct kye_tablet_info *info;
-	unsigned int newsize;
+	__u8 *newdesc = rdesc;
 
 	if (*rsize < sizeof(kye_tablet_rdesc)) {
 		hid_warn(hdev,
@@ -420,36 +424,45 @@  static __u8 *kye_tablet_fixup(struct hid_device *hdev, __u8 *rdesc, unsigned int
 		return rdesc;
 	}
 
-	newsize = info->has_punk ? sizeof(kye_tablet_rdesc) : 112;
-	memcpy(rdesc, kye_tablet_rdesc, newsize);
-
-	put_unaligned_le32(info->x_logical_maximum, rdesc + 66);
-	put_unaligned_le32(info->x_physical_maximum, rdesc + 72);
-	rdesc[77] = info->unit;
-	rdesc[79] = info->unit_exponent;
-	put_unaligned_le32(info->y_logical_maximum, rdesc + 87);
-	put_unaligned_le32(info->y_physical_maximum, rdesc + 92);
-	put_unaligned_le32(info->pressure_logical_maximum, rdesc + 104);
-
-	if (info->has_punk) {
-		put_unaligned_le32(info->x_logical_maximum, rdesc + 156);
-		put_unaligned_le32(info->x_physical_maximum, rdesc + 162);
-		rdesc[167] = info->unit;
-		rdesc[169] = info->unit_exponent;
-		put_unaligned_le32(info->y_logical_maximum, rdesc + 177);
-		put_unaligned_le32(info->y_physical_maximum, rdesc + 182);
+	memcpy(newdesc, kye_tablet_rdesc, sizeof(kye_tablet_rdesc));
+
+	put_unaligned_le32(info->x_logical_maximum, newdesc + 66);
+	put_unaligned_le32(info->x_physical_maximum, newdesc + 72);
+	newdesc[77] = info->unit;
+	newdesc[79] = info->unit_exponent;
+	put_unaligned_le32(info->y_logical_maximum, newdesc + 87);
+	put_unaligned_le32(info->y_physical_maximum, newdesc + 92);
+	put_unaligned_le32(info->pressure_logical_maximum, newdesc + 104);
+
+	newdesc += sizeof(kye_tablet_rdesc);
+
+	if (info->has_mouse) {
+		if (newdesc + sizeof(kye_tablet_mouse_rdesc) > rdesc + *rsize)
+			hid_err(hdev, "control desc unexpectedly large\n");
+		else {
+			memcpy(newdesc, kye_tablet_mouse_rdesc, sizeof(kye_tablet_mouse_rdesc));
+
+			put_unaligned_le32(info->x_logical_maximum, newdesc + 44);
+			put_unaligned_le32(info->x_physical_maximum, newdesc + 50);
+			newdesc[55] = info->unit;
+			newdesc[57] = info->unit_exponent;
+			put_unaligned_le32(info->y_logical_maximum, newdesc + 65);
+			put_unaligned_le32(info->y_physical_maximum, newdesc + 70);
+
+			newdesc += sizeof(kye_tablet_mouse_rdesc);
+		}
 	}
 
 	if (info->control_rsize) {
-		if (newsize + info->control_rsize > *rsize)
-			hid_err(hdev, "control rdesc unexpectedly large");
+		if (newdesc + info->control_rsize > rdesc + *rsize)
+			hid_err(hdev, "control desc unexpectedly large\n");
 		else {
-			memcpy(rdesc + newsize, info->control_rdesc, info->control_rsize);
-			newsize += info->control_rsize;
+			memcpy(newdesc, info->control_rdesc, info->control_rsize);
+			newdesc += info->control_rsize;
 		}
 	}
 
-	*rsize = newsize;
+	*rsize = newdesc - rdesc;
 	return rdesc;
 }