On Wed, Dec 02, 2009 at 12:30:29PM -0500, Jon Smirl wrote: > On Wed, Dec 2, 2009 at 12:10 PM, Dmitry Torokhov > <dmitry.torokhov@xxxxxxxxx> wrote: > > On Wed, Dec 02, 2009 at 10:44:58AM -0200, Mauro Carvalho Chehab wrote: > >> Dmitry Torokhov wrote: > >> > On Tue, Dec 01, 2009 at 07:05:49PM -0200, Mauro Carvalho Chehab wrote: > >> >> Dmitry Torokhov wrote: > >> >>> On Tue, Dec 01, 2009 at 05:00:40PM -0200, Mauro Carvalho Chehab wrote: > >> >>>> Dmitry Torokhov wrote: > >> >>>>> On Tue, Dec 01, 2009 at 03:29:44PM -0200, Mauro Carvalho Chehab wrote: > >> >>>>>> For sure we need to add an EVIOSETPROTO ioctl to allow the driver > >> >>>>>> to change the protocol in runtime. > >> >>>>>> > >> >>>>> Mauro, > >> >>>>> > >> >>>>> I think this kind of confuguration belongs to lirc device space, > >> >>>>> not input/evdev. This is the same as protocol selection for psmouse > >> >>>>> module: while it is normally auto-detected we have sysfs attribute to > >> >>>>> force one or another and it is tied to serio device, not input > >> >>>>> device. > >> >>>> Dmitry, > >> >>>> > >> >>>> This has nothing to do with the raw interface nor with lirc. This problem > >> >>>> happens with the evdev interface and already affects the in-kernel drivers. > >> >>>> > >> >>>> In this case, psmouse is not a good example. With a mouse, when a movement > >> >>>> occurs, you'll receive some data from its port. So, a software can autodetect > >> >>>> the protocol. The same principle can be used also with a raw pulse/space > >> >>>> interface, where software can autodetect the protocol. > >> >>> Or, in certain cases, it can not. > >> >>> > >> >>> [... skipped rationale for adding a way to control protocol (with which > >> >>> I agree) ...] > >> >>> > >> >>>> To solve this, we really need to extend evdev API to do 3 things: enumberate the > >> >>>> supported protocols, get the current protocol(s), and select the protocol(s) that > >> >>>> will be used by a newer table. > >> >>>> > >> >>> And here we start disagreeing. My preference would be for adding this > >> >>> API on lirc device level (i.e. /syc/class/lirc/lircX/blah namespace), > >> >>> since it only applicable to IR, not to input devices in general. > >> >>> > >> >>> Once you selected proper protocol(s) and maybe instantiated several > >> >>> input devices then udev (by examining input device capabilities and > >> >>> optionally looking up at the parent device properties) would use > >> >>> input evdev API to load proper keymap. Because translation of > >> >>> driver-specific codes into standard key definitions is in the input > >> >>> realm. Reading these driver-specific codes from hardware is outside of > >> >>> input layer domain. > >> >>> > >> >>> Just as psmouse ability to specify protocol is not shoved into evdev; > >> >>> just as atkbd quirks (force release key list and other driver-specific > >> >>> options) are not in evdev either; we should not overload evdev interface > >> >>> with IR-specific items. > >> >> I'm not against mapping those features as sysfs atributes, but they don't belong > >> >> to lirc, as far as I understand. From all we've discussed, we'll create a lirc > >> >> interface to allow the direct usage of raw IO. However, IR protocol is a property > >> >> that is not related to raw IO mode but, instead, to evdev mode. > >> >> > >> > > >> > Why would protocol relate to evdev node? Evdev does not really care what > >> > how the fact that a certain button was pressed was communicated to it. > >> > It may be deliveretd through PS/2 port, or maybe it was Bluetooth HID, > >> > or USB HID or USB boot protocol or some custom protocol, or RC-5, NEC or > >> > some custom IR protocol. It makes no difference _whatsoever_ to evdev > >> > nor any users of evdev care about protocol used by underlying hardware > >> > device to transmit the data. > >> > > >> >> We might add a /sys/class/IR and add IR specific stuff there, but it seems > >> >> overkill to me and will hide the fact that those parameters are part of the evdev > >> >> interface. > >> >> > >> >> So, I would just add the IR sysfs parameters at the /sys/class/input, if > >> >> the device is an IR (or create it is /sys/class/input/IR). > >> >> > >> >> I agree that the code to implement the IR specific sysfs parameter should be kept > >> >> oustide input core, as they're specific to IR implementations. > >> >> > >> >> Would this work for you? > >> > > >> > I am seeing a little bit differently structured subsystem for IR at the > >> > moment. I think we should do something like this: > >> > > >> > - receivers create /sys/class/lirc devices. These devices provide API > >> > with a ring buffer (fifo) for the raw data stream coming from (and to) > >> > them. > >> > >> The raw interface applies only to the devices that doesn't have a hardware decoder > >> (something between 40%-60% of the currently supported devices). > > > > 50% is quite a number I think. But if driver does not allow access to > > the raw stream - it will refuse binding to lirc_dev interface. > > > >> > >> > - we allow registering several data interfaces/decoders that can be bound > >> > (manually or maybe automatically) to lirc devices. lirc devices may > >> > provide hints as to which interface(s) better suited for handling the > >> > data coming form particular receiver. Several interfaces may be bound > >> > to one device at a time. > >> > - one of the interfaces is interface implementing current lirc_dev > >> > - other interfaces may be in-kernel RC-5 decoder or other decoders. > >> > decoders will create instances of input devices > >> > >> I don't see why having more than one interface, especially for devices with > >> hardware decoders. > >> > >> On IR remote receivers, internally, there's just one interface per hardware. > >> > >> Considering the hardware decoding case, why to artificially create other > >> interfaces that can't be used simultaneously? No current hardware > >> decoders can do that (or, at least, no current implementation allows). > >> We're foreseen some cases where we'll have that (like Patrick's dib0700 driver), > >> but for now, it is not possible to offer more than one interface to userspace. > >> Creating an arbitrary number of artificial interfaces just to pass a parameter > >> to the driver (the protocol), really seems overkill to me. > > > > We need to cater to the future cases as well. I don't want to redesign > > it in 2 years. But for devices that have only hardware decoders I > > suppose we can short-curcuit "interfaces" and have a library-like module > > creating input devices directly. > > > >> > >> In the case of the cheap devices with just raw interfaces, running in-kernel > >> decoders, while it will work if you create one interface per protocol > >> per IR receiver, this also seems overkill. Why to do that? It sounds that it will > >> just create additional complexity at the kernelspace and at the userspace, since > >> now userspace programs will need to open more than one device to receive the > >> keycodes. > > > > _Yes_!!! You open as many event devices as there are devices you are > > interested in receiving data from. Multiplexing devices are bad, bad, > > bad. Witness /dev/input/mouse and all the attempts at working around the > > fact that if you have a special driver for one of your devices you > > receive events from the same device through 2 interfaces and all kind of > > "grab", "super-grab", "smart-grab" schemes are born. > > > >> > >> > (for each remote/substream that they can recognize). > >> > >> I'm assuming that, by remote, you're referring to a remote receiver (and not to > >> the remote itself), right? > > > > If we could separate by remote transmitter that would be the best I > > think, but I understand that it is rarely possible? > > The code I posted using configfs did that. Instead of making apps IR > aware it mapped the vendor/device/command triplets into standard Linux > keycodes. Each remote was its own evdev device. > That is what I liked about the patchset. > That scheme could be made to "just work" by building in a couple of > mapping tables. The driver would pre-populate configfs entries for a > some standard IR devices. Set the remote for Motorala DVR. Default > Myth to look for the evdev device associated with Motorola DVR. The > built-in mapping table would then map from pulse timing to Linux > keycodes. > > If everyone hates configfs the same mapping can be done via the set > keys IOCTL and making changes to the user space apps like loadkeys. > It is not the hate of configfs per se, but rather concern that configfs takes too much resources and is not normally enabled. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
