On Fri, Dec 09, 2022 at 09:26, Jason Andryuk <jandryuk@xxxxxxxxx> wrote: > xen kbdfront registers itself as being able to deliver *any* key since > it doesn't know what keys the backend may produce. > > Unfortunately, the generated modalias gets too large and uevent creation > fails with -ENOMEM. > > This can lead to gdm not using the keyboard since there is no seat > associated [1] and the debian installer crashing [2]. > > Trim the ranges of key capabilities by removing some BTN_* ranges. > While doing this, some neighboring undefined ranges are removed to trim > it further. > > An upper limit of KEY_KBD_LCD_MENU5 is still too large. Use an upper > limit of KEY_BRIGHTNESS_MENU. > > This removes: > BTN_DPAD_UP(0x220)..BTN_DPAD_RIGHT(0x223) > Empty space 0x224..0x229 > > Empty space 0x28a..0x28f > KEY_MACRO1(0x290)..KEY_MACRO30(0x2ad) > KEY_MACRO_RECORD_START 0x2b0 > KEY_MACRO_RECORD_STOP 0x2b1 > KEY_MACRO_PRESET_CYCLE 0x2b2 > KEY_MACRO_PRESET1(0x2b3)..KEY_MACRO_PRESET3(0xb5) > Empty space 0x2b6..0x2b7 > KEY_KBD_LCD_MENU1(0x2b8)..KEY_KBD_LCD_MENU5(0x2bc) > Empty space 0x2bd..0x2bf > BTN_TRIGGER_HAPPY(0x2c0)..BTN_TRIGGER_HAPPY40(0x2e7) > Empty space 0x2e8..0x2ff > > The modalias shrinks from 2082 to 1550 bytes. > > A chunk of keys need to be removed to allow the keyboard to be used. > This may break some functionality, but the hope is these macro keys are > uncommon and don't affect any users. > > [1] https://github.com/systemd/systemd/issues/22944 > [2] https://lore.kernel.org/xen-devel/87o8dw52jc.fsf@xxxxxxxxxxxxxxxx/T/ > > Cc: Phillip Susi <phill@xxxxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx> Reviewed-by: Mattijs Korpershoek <mkorpershoek@xxxxxxxxxxxx> > --- > drivers/input/misc/xen-kbdfront.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > v2: > Remove more keys: v1 didn't remove enough and modalias was still broken. > > diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c > index 8d8ebdc2039b..4ecb579df748 100644 > --- a/drivers/input/misc/xen-kbdfront.c > +++ b/drivers/input/misc/xen-kbdfront.c > @@ -256,7 +256,14 @@ static int xenkbd_probe(struct xenbus_device *dev, > __set_bit(EV_KEY, kbd->evbit); > for (i = KEY_ESC; i < KEY_UNKNOWN; i++) > __set_bit(i, kbd->keybit); > - for (i = KEY_OK; i < KEY_MAX; i++) > + /* In theory we want to go KEY_OK..KEY_MAX, but that grows the > + * modalias line too long. There is a gap of buttons from > + * BTN_DPAD_UP..BTN_DPAD_RIGHT and KEY_ALS_TOGGLE is the next > + * defined. Then continue up to KEY_BRIGHTNESS_MENU as an upper > + * limit. */ > + for (i = KEY_OK; i < BTN_DPAD_UP; i++) > + __set_bit(i, kbd->keybit); > + for (i = KEY_ALS_TOGGLE; i <= KEY_BRIGHTNESS_MENU; i++) > __set_bit(i, kbd->keybit); > > ret = input_register_device(kbd); > -- > 2.38.1
