Date: Sun, 17 Feb 2019 16:00:32 -0600 From: "Apollo D. Sharpe, Sr." <demetrioussharpe@netscape.net> To: Hans Petter Selasky <hps@selasky.org>, freebsd-usb@freebsd.org Subject: Re: Questions about the USB HID device drivers Message-ID: <3724cc29-b682-2395-bd95-cbfa418ad9f2@netscape.net> In-Reply-To: <6762c7c9-f9dc-f7d2-0b1f-c2f6e2816cd7@selasky.org> References: <fd7883c8-604e-e7d7-b135-d1d957938e7c@netscape.net> <9c6a87dd-cf7c-d0eb-82f1-5e904baaf05f@selasky.org> <325834a2-d9f1-a1f4-dff1-7f724aeb4907@netscape.net> <6762c7c9-f9dc-f7d2-0b1f-c2f6e2816cd7@selasky.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On 2/15/19 7:46 AM, Hans Petter Selasky wrote: > On 2/15/19 2:22 PM, A. D. Sharpe wrote: >> On 2/15/2019 3:30 AM, Hans Petter Selasky wrote: >>> >>> Did you have a look at the code? >>> >>> sys/dev/usb/input/ums.c and sys/dev/usb/input/ukbd.c >> I think I have a decent understanding of USB devices under FreeBSD. >> However, two things are tripping me up: a) the fact that the ums & >> ukbd drivers don't have "make_dev()" calls in them; and b) I can't >> seem to find an overall keyboard system or overall mouse system. >> > > Events are delivered from the USB INTERRUPT endpoint's completion > handler to various places. At the moment events can end up via EVDEV > or simply sysmouse or the regular keyboard API depending on the system > configuration. > > At the moment, only for EVDEVS's /dev/input/xxxx, there is a > per-device character device handle, I think. I think I've gotten a pretty good understanding of what's going on now, based on the answers that I've gotten from the developers part of the FreeBSD forums(*). The USB keyboard and mouse paths seems to go like this: ums->usb_hid->/dev/ums0->sysmouse ukbd->usb_hid->/dev/ukbd0->kbdmux If this is correct, then the majority of my inquiry has been satisfied. My next questions are more centered around /dev as it relates to device drivers in general: 1. Is there a published standard of how device drivers should publish themselves in /dev? From what I can tell, they seem to be thrown into /dev without any sort of hierarchy to organize the nodes into what type of device they represent. 2. Does usb_hid automatically dump device nodes into /dev, or is there a way for hid drivers to specify specifically where their nodes should be publish -such as: /dev/input/somehiddevice0 ? (*) https://forums.freebsd.org/threads/questions-about-the-usb-hid-device-drivers.69604/ -- Regards, Apollo D. Sharpe, Sr.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3724cc29-b682-2395-bd95-cbfa418ad9f2>