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@vps.thesusis.net/T/
Cc: Phillip Susi phill@thesusis.net Cc: stable@vger.kernel.org Signed-off-by: Jason Andryuk jandryuk@gmail.com --- 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);