On Sat, 5 May 2012, Martin Mokrejs wrote: > > Help for what? Do you want to know why the 2105 doesn't work very > > well? > > Yes. And whether ehci_hcd is doing the right thing in each case and whether > there is a reason different trajectories were taken. ;-) ehci-hcd is definitely doing the right thing in each case. The reason for the different outcomes is because the device behaved differently each time. That is, it started working correctly at different points during the initialization sequence. > > My impression is that it turns on the electrical connection to the > > computer before it is fully set up and ready to operate. As a result, > > the first one or two times it can't respond properly when the computer > > tries to initialize it. > > You talk about the above dmesg which was in the body of the email, right? No, I was speaking about all your logs, including the dmesg logs and also the corresponding usbmon traces. > That was the case when it failed completely to catch up. Unfortunately, I > wasn't able to reproduce but at least I collected traces for 4 distinct > situations. > > So how about those attached files (4 cases, each dmesg + usbmon)? There are also > errors but *were overcome*. That's because the device eventually started working right. In the case where it failed completely, it never did work right. > Still I thought it is good to think of them. Well, > stuff for you if you have time and maybe can find that linux could do better. No, the fault lies entirely with the device. There's not much Linux can do when the device doesn't send any response, except log an error message and try again -- which is what you saw. 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
