| Message ID | 20181004123430.29348-1-benjamin.tissoires@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] Input: reserve 2 events code because of HID | expand |
On Thu, Oct 04, 2018 at 02:34:30PM +0200, Benjamin Tissoires wrote: > Prior to commit 190d7f02ce8e ("HID: input: do not increment usages when > a duplicate is found") from the v4.18 kernel, HID used to shift the > event codes if a duplicate usage was found. This ended up in a situation > where a device would export a ton of ABS_MISC+n event codes, or a ton > of REL_MISC+n event codes. > > This is now fixed, however userspace needs to detect those situation. > Fortunately, ABS_MT_SLOT-1 (ABS_MISC+6) was never assigned a code, and > so libinput can detect fake multitouch devices from genuine ones by > checking if ABS_MT_SLOT-1 is set. > > Now that we have REL_WHEEL_HI_RES, libinput won't be able to differentiate > true high res mice from some other device in a pre-v4.18 kernel. > > Set in stone that the ABS_MISC+6 and REL_MISC+1 are reserved and should not > be used so userspace can properly work around those old kernels. > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> > --- > > Dmitry, I did not take your Acked-by, as I added 2 new events and wanted to > be sure you are still OK. Yes, this is still fine. Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > > Jiri, this will still need to go through your tree, as the input-event-codes > changes that introduce REL_WHEEL_HI_RES are in your for-4.20/logitech-highres. > > Cheers, > Benjamin > > include/uapi/linux/input-event-codes.h | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h > index 29fb891ea337..b5e0e9856c47 100644 > --- a/include/uapi/linux/input-event-codes.h > +++ b/include/uapi/linux/input-event-codes.h > @@ -708,7 +708,15 @@ > #define REL_DIAL 0x07 > #define REL_WHEEL 0x08 > #define REL_MISC 0x09 > -#define REL_WHEEL_HI_RES 0x0a > +/* > + * 0x0a is reserved and should not be used in input drivers. > + * It was used by HID as REL_MISC+1 and userspace needs to detect if > + * the next REL_* event is correct or is just REL_MISC + n. > + * We define here REL_RESERVED so userspace can rely on it and detect > + * the situation described above. > + */ > +#define REL_RESERVED 0x0a > +#define REL_WHEEL_HI_RES 0x0b > #define REL_MAX 0x0f > #define REL_CNT (REL_MAX+1) > > @@ -745,6 +753,15 @@ > > #define ABS_MISC 0x28 > > +/* > + * 0x2e is reserved and should not be used in input drivers. > + * It was used by HID as ABS_MISC+6 and userspace needs to detect if > + * the next ABS_* event is correct or is just ABS_MISC + n. > + * We define here ABS_RESERVED so userspace can rely on it and detect > + * the situation described above. > + */ > +#define ABS_RESERVED 0x2e > + > #define ABS_MT_SLOT 0x2f /* MT slot being modified */ > #define ABS_MT_TOUCH_MAJOR 0x30 /* Major axis of touching ellipse */ > #define ABS_MT_TOUCH_MINOR 0x31 /* Minor axis (omit if circular) */ > -- > 2.14.3 >
On Thu, 4 Oct 2018, Benjamin Tissoires wrote: > Prior to commit 190d7f02ce8e ("HID: input: do not increment usages when > a duplicate is found") from the v4.18 kernel, HID used to shift the > event codes if a duplicate usage was found. This ended up in a situation > where a device would export a ton of ABS_MISC+n event codes, or a ton > of REL_MISC+n event codes. > > This is now fixed, however userspace needs to detect those situation. > Fortunately, ABS_MT_SLOT-1 (ABS_MISC+6) was never assigned a code, and > so libinput can detect fake multitouch devices from genuine ones by > checking if ABS_MT_SLOT-1 is set. > > Now that we have REL_WHEEL_HI_RES, libinput won't be able to differentiate > true high res mice from some other device in a pre-v4.18 kernel. > > Set in stone that the ABS_MISC+6 and REL_MISC+1 are reserved and should not > be used so userspace can properly work around those old kernels. > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> > --- > > Dmitry, I did not take your Acked-by, as I added 2 new events and wanted to > be sure you are still OK. > > Jiri, this will still need to go through your tree, as the input-event-codes > changes that introduce REL_WHEEL_HI_RES are in your for-4.20/logitech-highres. Applied, thanks Benjamin.
diff --git a/include/uapi/linux/input-event-codes.h b/include/uapi/linux/input-event-codes.h index 29fb891ea337..b5e0e9856c47 100644 --- a/include/uapi/linux/input-event-codes.h +++ b/include/uapi/linux/input-event-codes.h @@ -708,7 +708,15 @@ #define REL_DIAL 0x07 #define REL_WHEEL 0x08 #define REL_MISC 0x09 -#define REL_WHEEL_HI_RES 0x0a +/* + * 0x0a is reserved and should not be used in input drivers. + * It was used by HID as REL_MISC+1 and userspace needs to detect if + * the next REL_* event is correct or is just REL_MISC + n. + * We define here REL_RESERVED so userspace can rely on it and detect + * the situation described above. + */ +#define REL_RESERVED 0x0a +#define REL_WHEEL_HI_RES 0x0b #define REL_MAX 0x0f #define REL_CNT (REL_MAX+1) @@ -745,6 +753,15 @@ #define ABS_MISC 0x28 +/* + * 0x2e is reserved and should not be used in input drivers. + * It was used by HID as ABS_MISC+6 and userspace needs to detect if + * the next ABS_* event is correct or is just ABS_MISC + n. + * We define here ABS_RESERVED so userspace can rely on it and detect + * the situation described above. + */ +#define ABS_RESERVED 0x2e + #define ABS_MT_SLOT 0x2f /* MT slot being modified */ #define ABS_MT_TOUCH_MAJOR 0x30 /* Major axis of touching ellipse */ #define ABS_MT_TOUCH_MINOR 0x31 /* Minor axis (omit if circular) */
Prior to commit 190d7f02ce8e ("HID: input: do not increment usages when a duplicate is found") from the v4.18 kernel, HID used to shift the event codes if a duplicate usage was found. This ended up in a situation where a device would export a ton of ABS_MISC+n event codes, or a ton of REL_MISC+n event codes. This is now fixed, however userspace needs to detect those situation. Fortunately, ABS_MT_SLOT-1 (ABS_MISC+6) was never assigned a code, and so libinput can detect fake multitouch devices from genuine ones by checking if ABS_MT_SLOT-1 is set. Now that we have REL_WHEEL_HI_RES, libinput won't be able to differentiate true high res mice from some other device in a pre-v4.18 kernel. Set in stone that the ABS_MISC+6 and REL_MISC+1 are reserved and should not be used so userspace can properly work around those old kernels. Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> --- Dmitry, I did not take your Acked-by, as I added 2 new events and wanted to be sure you are still OK. Jiri, this will still need to go through your tree, as the input-event-codes changes that introduce REL_WHEEL_HI_RES are in your for-4.20/logitech-highres. Cheers, Benjamin include/uapi/linux/input-event-codes.h | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)