On Thu, Oct 20, 2022 at 8:21 AM Jason Andryuk <jandryuk@xxxxxxxxx> wrote: > > On Thu, Oct 20, 2022 at 4:31 AM Mattijs Korpershoek > <mkorpershoek@xxxxxxxxxxxx> wrote: > > > > On Wed, Oct 19, 2022 at 16:14, 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. > > > > > > 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@xxxxxxxxxxxxxxxx/T/ > > > > > > Cc: Phillip Susi <phill@xxxxxxxxxxxx> > > > Cc: stable@xxxxxxxxxxxxxxx > > > Signed-off-by: Jason Andryuk <jandryuk@xxxxxxxxx> > > > > Reviewed-by: Mattijs Korpershoek <mkorpershoek@xxxxxxxxxxxx> > > This patch doesn't work and needs to be withdrawn.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++) Changing the upper bound to KEY_BRIGHTNESS_MENU works. That trims out KEY_MACRO* and KEY_KBD_LCD_MENU*. Something has to get trimmed out to bring the size down. These are probably less common and okay to remove, but I'm just guessing. Regards, Jason
