| Message ID | 20221019201458.21803-1-jandryuk@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Input: xen-kbdfront - drop keys to shrink modalias | expand |
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> > --- > 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
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
On Thu, Oct 20, 2022 at 8:21 AM Jason Andryuk <jandryuk@gmail.com> wrote: > > 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++) 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
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);
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> --- drivers/input/misc/xen-kbdfront.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)