Re: 2.6.36/2.6.37: broken compatibility with userspace input-utils ?

Dmitry Torokhov
2011-01-25T04:56:07Z

On Mon, Jan 24, 2011 at 11:37:06PM -0500, Mark Lord wrote:
> On 11-01-24 11:20 PM, Dmitry Torokhov wrote:
> > On Mon, Jan 24, 2011 at 11:13:05PM -0500, Mark Lord wrote:
> >> On 11-01-24 07:55 PM, Dmitry Torokhov wrote:
> >>>
> >>> No, as far as I know we kept ABI intact.
> >>
> >>
> >> Okay, I hacked lsinput and input-kbd to ignore the protocol number.
> >> input-kbd is still broken: it thinks my remote control (Hauppauge)
> >> has only ten buttons, and won't allow me to remap codes larger than 10.
> >>
> >> I've now hacked around that too, but without determining exactly
> >> where the interface got broken.
> >>
> >> Ugh.
> >>
> >
> > Where are the sources? I can take a look...
>
> I used "apt-get source input-utils" under Ubuntu-10.10.
> The problem seems to be here somewhere:
>
> static struct kbd_map* kbd_map_read(int fd)
> {
> struct kbd_entry entry;
> struct kbd_map *map;
> int rc;
>
> map = malloc(sizeof(*map));
> memset(map,0,sizeof(*map));
> for (map->size = 0; map->size < 65536; map->size++) {
> entry.scancode = map->size;
> entry.keycode = KEY_RESERVED;
> rc = ioctl(fd, EVIOCGKEYCODE, &entry);
> if (rc < 0) {
> break;
> }
> if (map->size >= map->alloc) {
> map->alloc += 64;
> map->map = realloc(map->map, map->alloc * sizeof(entry));
> }
> map->map[map->size] = entry;
>
> if (KEY_RESERVED != entry.keycode)
> map->keys++;
> }
> if (map->keys) {
> printf("map: %d keys, size: %d/%d\n",
> map->keys, map->size, map->alloc);
> return map;
> } else {
> free(map);
> return NULL;
> }
> }
>
> This results in (map->size==10) for 2.6.36+ (wrong),
> and a much larger map->size for 2.6.35 and earlier.
>
> So perhaps EVIOCGKEYCODE has changed?
>

So the utility expects that all devices have flat scancode space and
driver might have changed so it does not recognize scancode 10 as valid
scancode anymore.

The options are:

1. Convert to EVIOCGKEYCODE2
2. Ignore errors from EVIOCGKEYCODE and go through all 65536 iterations.

Thanks.

--
Dmitry