I'm also confused on this. My company developed some switchable devices (3G modems), and we use libusb (user space) to send control command to device. However, users need to install switch mode application, when they plug-in this device on first time. Huawei devices, they could be identified on storage mode, and then sent switch command from kernel. Most users like this kind of behavior (automatic switch without installation), and I consider to submit this kind of patch, but I don't think this kind behavior should be in kernel. Do we have other way to meet this kind of requirement, automatic switch without installation? Regards, Brad. -----Original Message----- From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb-owner@xxxxxxxxxxxxxxx] On Behalf Of Oliver Neukum Sent: Monday, June 22, 2009 4:06 AM To: Josua Dietze Cc: Linux USB Subject: Re: Switchable devices (storage/serial) Am Sonntag, 21. Juni 2009 21:43:52 schrieb Josua Dietze: > Oliver Neukum schrieb: > > Am Sonntag, 21. Juni 2009 18:51:44 schrieb Josua Dietze: > >> I have accumulated some information about these weird hybrid > >> devices, mostly wireless modems. I am now convinced that ambiguities > >> and side effects can be handled when switching these devices in the > >> usb-storage code. > > > > The question is whether this needs to be done in kernel space at all. > > We do need this code in kernel space if we want to do reset_resume() > > for those devices, but we'd need a lot more infrastructure which we don't > > have right now. > > Now I'm confused: I thought it was agreed to add switching functions > to the kernel ... > > If this is not wanted, why are there such functions for Option, > Huawei and Sierra devices? I don't know. Presumably there was a good reason. Go ahead, implementing this is fine to me. > If there is a decision to do switching in userspace, fine; but then > let it stay there. As an author of an userspace switching tool I'd > prefer clear standards. > On several occasions I was surprised by kernel updates which > interfered with what I was doing (like a well-meant IGNORE_DEVICE in > "uusual_devs"). My mistake was of course not to be on this list ... > > I don't think reset_resume() has any relevance in connection with > switching devices. The ones I'm referring to just "disappear" from > the system and come back as a "new device" when switched, most of > them with a different ID. So usb-storage just needs to send the bulk The question is what we do if power to USB is cut during suspend. The devices will revert to their storage role. Regards Oliver -- 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 *************************** The opinions and views expressed in this e-mail are solely those of the author and do not necessarily represent those of Qisda Corporation and its affiliates. Qisda Corporation is not responsible for any liability or damaged caused by viruses transmitted with this e-mail or its attachments. If this e-mail is not originally intended for you, or received by you in error, do not disclose its content to anyone and delete it immediately. This e-mail may contain information that is private, legally privileged, confidential or exempt from disclosure, and intended for the sole use of the intended recipient. Any review, copying, or distribution of this email (or any attachments thereto) by others is strictly prohibited. Thank you. -- 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
