Re: Questions about the USB HID device drivers
On 2/18/19 3:37 PM, Ian Lepore wrote: Not to userland applications so much as to sysadmin-controlled configuration which is applied from userland during system startup and when new devices are attached. See the manpage for devfs.conf. Which does make sense on servers & network infrastructure. However, I'm wondering if there's a better way to do this for systems that aren't expected to have a sysadmin -basic desktop systems. From the kernel side, some subsystems do create a hierarchy (or at least a subdir for a set of related devices), and others don't. There is no system-wide policy about it either way. I have to admit that I'm surprised that there's no system-wide policy for this. -- Regards, Apollo D. Sharpe, Sr. ___ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: Questions about the USB HID device drivers
On 2/18/19 3:18 PM, Warner Losh wrote: Yes and no. If the unique prefix has / in it, devfs puts it in a subdir. If I'm reading the code right, the unique prefix is basically driver_t::name. Is that correct? If so, I haven't seen a device name (in the entire tree) that has "/" in it's device name. Maybe I'm missing something here. Way back in the days of yore, it was 100% userland to create the hierarchy. You did your mknod and that was that. We had big tables of major numbers that mapped device names to the kernel. There were problems with this: not the least was that major numbers were a limited resource and soon ran out. Now, devfs manages everything. You can get it to create many different hierarchies. see devfs(8) for details. I can imagine how much of a pain that was. Though, it looks as though not too many people bother changing beyond the default devfs.rules and devfs.conf files -they also seem to be a pain to deal with. It's a reasonable solution for servers, however it would be much more valuable on desktops to have /dev/input/* for various input devices. I guess I'm going to have to figure out how to make devices publish themselves in /dev based on their primary function. Thank you, and everyone else, for taking the time to explain the setup to me. -- Regards, Apollo D. Sharpe, Sr. ___ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: Questions about the USB HID device drivers
On Mon, 2019-02-18 at 15:03 -0600, Apollo D. Sharpe, Sr. via freebsd- usb wrote: > On 2/18/19 3:26 AM, Hans Petter Selasky wrote: > > Each devicename has a uniq prefix followed by a uniq unit number. > > So, we just end up dumping ALL device nodes in /dev... > > > > Character device nodes are automatically created. However it is > > possible for user-space applications to create symbolic links > > afterwards in /dev . > > ...and leave it to user-space to create the hierarchy within /dev? > Is > there a technical reason that kernel drivers don't automatically > subscribe to a hierarchy, or is this just historic inertia? It seems > funny to me that such decisions are left to user-space applications. > > Not to userland applications so much as to sysadmin-controlled configuration which is applied from userland during system startup and when new devices are attached. See the manpage for devfs.conf. >From the kernel side, some subsystems do create a hierarchy (or at least a subdir for a set of related devices), and others don't. There is no system-wide policy about it either way. -- Ian ___ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: Questions about the USB HID device drivers
On Mon, Feb 18, 2019 at 2:04 PM Apollo D. Sharpe, Sr. via freebsd-usb < freebsd-usb@freebsd.org> wrote: > On 2/18/19 3:26 AM, Hans Petter Selasky wrote: > > Each devicename has a uniq prefix followed by a uniq unit number. > > So, we just end up dumping ALL device nodes in /dev... > Yes and no. If the unique prefix has / in it, devfs puts it in a subdir. > > Character device nodes are automatically created. However it is > > possible for user-space applications to create symbolic links > > afterwards in /dev . > > ...and leave it to user-space to create the hierarchy within /dev? Is > there a technical reason that kernel drivers don't automatically > subscribe to a hierarchy, or is this just historic inertia? It seems > funny to me that such decisions are left to user-space applications. > Way back in the days of yore, it was 100% userland to create the hierarchy. You did your mknod and that was that. We had big tables of major numbers that mapped device names to the kernel. There were problems with this: not the least was that major numbers were a limited resource and soon ran out. Now, devfs manages everything. You can get it to create many different hierarchies. see devfs(8) for details. Warner ___ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: Questions about the USB HID device drivers
On 2/18/19 3:26 AM, Hans Petter Selasky wrote: Each devicename has a uniq prefix followed by a uniq unit number. So, we just end up dumping ALL device nodes in /dev... Character device nodes are automatically created. However it is possible for user-space applications to create symbolic links afterwards in /dev . ...and leave it to user-space to create the hierarchy within /dev? Is there a technical reason that kernel drivers don't automatically subscribe to a hierarchy, or is this just historic inertia? It seems funny to me that such decisions are left to user-space applications. -- Regards, Apollo D. Sharpe, Sr. ___ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: Questions about the USB HID device drivers
On 2/17/19 11:00 PM, Apollo D. Sharpe, Sr. wrote: 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/, 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: Hi, 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. Each devicename has a uniq prefix followed by a uniq unit number. 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 ? Character device nodes are automatically created. However it is possible for user-space applications to create symbolic links afterwards in /dev . (*) https://forums.freebsd.org/threads/questions-about-the-usb-hid-device-drivers.69604/ --HPS ___ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: Questions about the USB HID device drivers
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/, 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. ___ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
Re: Questions about the USB HID device drivers
On 2/15/19 1:44 AM, Apollo D. Sharpe, Sr. via freebsd-usb wrote: Hello, Specifically, I'm interested in how the USB keyboard & mouse drivers publish their nodes. I've been combing through the sources of both drivers in an attempt to understand a) how they make available the data from their devices, b) how they publish their device nodes, and c) where all of the code that implements both sets of sequences is stored at in the source tree. I currently see the ukb & ums driver sources. Beyond that, I'm not sure where to look in order to follow the path between those drivers & /dev. Can anyone help me understand this? Hi, Did you have a look at the code? sys/dev/usb/input/ums.c and sys/dev/usb/input/ukbd.c --HPS ___ freebsd-usb@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-usb To unsubscribe, send any mail to "freebsd-usb-unsubscr...@freebsd.org"
