On Thu, Oct 20, 2022 at 4:31 AM Mattijs Korpershoek mkorpershoek@baylibre.com wrote:
On Wed, Oct 19, 2022 at 16:14, Jason Andryuk jandryuk@gmail.com 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.
This removes: BTN_DPAD_UP(0x220)..BTN_DPAD_RIGHT(0x223) Empty space 0x224..0x229
Emtpy space 0x2bd..0x2bf BTN_TRIGGER_HAPPY(0x2c0)..BTN_TRIGGER_HAPPY40(0x2e7) Empty space 0x2e8..0x2ff
The modalias shrinks from 2082 to 1754 bytes.
[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
Reviewed-by: Mattijs Korpershoek mkorpershoek@baylibre.com
This patch doesn't work and needs to be withdrawn. My gdm/udev workaround was still active when I tested, so that is why I had a working keyboard. Sorry about that.
Now the question is, which additional keys can be omitted to trim the modalias to an acceptable size?
Regards, Jason
drivers/input/misc/xen-kbdfront.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/input/misc/xen-kbdfront.c b/drivers/input/misc/xen-kbdfront.c index 8d8ebdc2039b..23f37211be78 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. KEY_KBD_LCD_MENU5 is the last* defined non-button key. There is a gap of buttons from* BTN_DPAD_UP..BTN_DPAD_RIGHT and KEY_ALS_TOGGLE is the next* defined. */for (i = KEY_OK; i < BTN_DPAD_UP; i++)__set_bit(i, kbd->keybit);for (i = KEY_ALS_TOGGLE; i <= KEY_KBD_LCD_MENU5; i++) __set_bit(i, kbd->keybit); ret = input_register_device(kbd);-- 2.37.3