On Thu, Jan 24, 2013 at 06:30:21PM +0800, Lv Zheng wrote: > In the recent ACPI 5.0 specification updates, firmwares are provided the > possibilities to enumerate the UART slave devices known to the platform > vendors. > There are the needs in Linux to utilize the benefits: > 1. hotplug uevent > 2. serial configuration > Currently, only serial cards on the specific bus (ex. PCMCIA) can be > enumerated and userspace can obtain the hotplug event of the UART target > devices. Linux kernel is lack of an overall enumeration mechanism for > UART slave devices. Huh? That's flat out not true, otherwise how would userspace be creating the proper /dev/tty* nodes for all tty devices? > In order to send uevent, a device need to be a class device or a bus > device. This patch introduces a tty_enum bus since the enumerated slave > devices are expected to be physical devices. Again, tty devices are already class devices, and they send out uevents. You can see this today by watching the uevent stream using a tool like 'udevadmin monitor'. > When the UART slave devices are created, userspace uevent rules can > pass the creation details to the userspace driver managers > (ex. hciattach), then the device managers can read hardware IDs and the > serial configurations from the exported device attributes to match and > configure a userspace TTY device driver. What? We do that today, no kernel changes needed. > The created slave devices will be automatically unregistered when the > associated TTY ports are destructed. Again, this happens today. Or am I missing something big and major here? How have people been seeing and configuring their tty devices for the last 8+ years or so since the 2.6.0 kernel was released with uevent support for tty devices? lost, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
