On Sat, 5 May 2012, Martin Mokrejs wrote: > Greg Kroah-Hartman wrote: > > On Sat, May 05, 2012 at 02:14:43PM +0200, Martin Mokrejs wrote: > >> Paul Bolle wrote: > >>> Currently announce_device() does print the idVendor and idProduct values > >>> but does not print the bcdDevice value. USB devices are accurately > >>> identified by all three values. See, for instance, the USB storage > >>> quirks which will only apply for a certain (range of) bcdDevice > >>> value(s). So it seems useful to also print bcdDevice when announcing USB > >>> devices. > >> > >> Could it also report negotiated speed? full-speed, high-speed, super-speed? > > > > All of this, including the bcdDevice, can be found in sysfs. So I don't > > want to take this patch, otherwise we would be just adding more and more > > to the kernel log. > > > > If you programatically want to find this out, use libudev or listen to > > the dbus messages for new devices, don't watch the kernel log messages. > > Hmm, but when you go through your syslog/dmesg lines especially in case of > USB devices which you swap in and out quite often, it is too late to lookup > some file elsewhere which relates to *current* device. The information > is lost already if you changed device meanwhile. You just realize USB disk > disconnected but you have not way find out except from the log files what > speed did it use. In case of USB3 devices capable of lower speeds it is > quite important. Some just claim USB3 capabilities (on the package box) > but in real, always end up at high-speed only. > > For me testing several USB disks, USB to SATA bridges, host controllers, > kernel command-lines ... it is way to much work. Having the USB debug > enabled, especially XHCI_HCD_DEBUG gives on the other had too much output > for daily use but as this is all stuff prone to fail somewhere and at some > point I keep it enabled. > > I don't think it clutters syslog nor that it adds significant extra size > to the output. It would save people from enabling debug just because of this. > And no, average linux user never never lookup sysfs nor use libudev, really. > Still, the link speed is of interest to everybody fiddling with the stuff > and wondering why the damn thing is so slow or why did it disconnect. It gives > an answer or at least a hint. But the kernel _already_ logs a message listing new USB devices along with their speed. In fact, it does this even if the ANNOUNCE config option isn't set. Alan Stern -- 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
