Henrique de Moraes Holschuh wrote: > On Thu, 17 Sep 2009, Dmitry Torokhov wrote: >> On Thu, Sep 17, 2009 at 02:57:07PM -0300, Henrique de Moraes Holschuh >> wrote: >> > On Wed, 16 Sep 2009, Rick L. Vinyard, Jr. wrote: >> > > The M* keys are intended to provide a quick way to switch between >> key >> > > mappings, with each mode having their own user-defined mappings. >> > >> > What I'd do in this case would be this: >> > >> > 1. Initially have the M* level-shift keys assigned KEY_RESERVED >> > >> > 2. Have a big enough keymap to map all keys in all M*-level shift >> states >> > possible. >> > >> > Eg: >> > START OF KEYMAP >> > M* keys >> > 1st set of G* keys >> > 2nd set of G* keys >> > 3rd set of G* keys... >> > ... >> > last set of G* keys >> > END OF KEYMAP >> > >> > 3. Have the driver special-process M* level-shift keys *as long as >> they are >> > still set to KEY_RESERVED* to select which part of the keymap is used >> to >> > translate the other keys. Note that this likely means pressing a M* >> key >> > would be transparent to userspace in this case, i.e. no events would >> be >> > issued when a M* key is doing a level shift. >> > >> > So, you'd be able to set all mappings you want in the driver, and the >> M* >> > keys would do what they're expected to do without any userland help at >> all, >> > but you'd still be able to program the M* keys to be normal keys if >> you >> > want. >> > >> > Of course, this assumes you don't do chording on multiple M* keys to >> end up >> > with a huge number of keymaps :p >> >> Actually I think that the device should just emit KEY_PROG1..KEY_PROG4 >> for the M keys and have userspace daemon load alternate keymaps on the >> fly in resaponse to KEY_PROGx. The device is just a set of completely >> generic buttons... User will have to tell the kernel what to map them >> to. > > It would work, but it is a big trip through userspace. If quickly > pressing > M#+G# is a common use pattern (and it will be, for gaming), i.e. you often > want to access quickly a function on one level then another on a different > level, asking userspace to upload a new keymap to switch levels at every > M# > press is going to be way too racy. > > If it is to be used like that, I'd advocate either doing the entire > map-switching thing in kernel space, or doing the entire mapping in > userspace. In the later case, you don't issue KEY_* in the kernel driver, > you just issue MSC_SCAN events, and the userspace driver should open the > input device in exclusive mode, do its magic, and use uinput to generate > translated events (KEY_*, and even BTN_*, etc). > > I understand the current version allows for an all-userspace enhanced > driver > if one sets the entire keymap to KEY_RESERVED, since it will issue > MSC_SCAN > events for all keys (if it doesn't, I suggest doing so). It does. > That might > indeed > be the best option if one doesn't want a more complex kernel driver. And > one could still use the device in degraded mode by not loading the > userspace > driver, and uploading a regular keymap to it. > A keymap for three modes wouldn't be too bad space wise. I'd prefer to keep the input events in kernel space. I was trying to minimize the code in the driver, but I don't think it will increase it by that much. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
