Re: How to safe recover USB driver from broken hardware situation
On Tue, 23 Apr 2013, Peter Chen wrote: On Mon, Apr 22, 2013 at 11:26:05AM -0400, Alan Stern wrote: On Mon, 22 Apr 2013, Peter Chen wrote: Hi all, Recently, I have several customers troubled in safe recover USB function during the ESD situation (or some other situations, like short dp/dm, ground dp/dm, etc). I designed the ESD detect and recovery process, but I met some sync problems between host controller driver (eg, ehci) and class driver (eg, mass storage). For example, when khubd tries to disconnect usb device, it will try to stop thread usb-storage, but usb-storage is waiting some transfers to finish, qTD and QH operation may be finished (usb_submit_urb does not return error), but no watchdog timer and completion interrupt are occurred. I have: esd_detect_process and esd_recovery_process at host controller driver. At esd_detect_porcess It will disable usb interrupt and judge ASE and PSE, etc. At esd_recovery_process: It needs to reset controller (usbcmd.rst, and toggle portsc.pp bit, etc) I would like to have some synchronization mechanism between usb_submit_urb or (ehci_urb_enqueue) and my esd_detect_process and esd_recovery_process. But still not find a safe one, eg, I still met khubd's status changes D problem described above. Any suggestions are appreciated, Thanks. Your recovery process should not need to make all these changes to ehci-hcd. Simply carry out the same actions as the dead: statement label in ehci_irq() -- that is, do the same thing as if an interrupt occurred with the STS_FATAL bit set. That code is all properly synchronized. Sometimes, there are no STS_FATAL and STA_ERR when ESD occurs. So, you suggest do the same thing for STS_FATAL at my esd_recovery_process? Yes. Then unbind the driver from the controller and rebind it. Rebinding will reset the controller. You mean unbind the controller driver? Any existed API can be called? I can't do rmmod at that time. You can call device_release_driver, after locking both the controller's parent and the controller itself. See driver_unbind() in drivers/base/bus.c. Or, if you are doing this in userspace, you can write the controllers device name to /sys/bus/.../drivers/.../unbind. Alan Stern -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
How to safe recover USB driver from broken hardware situation
Hi all, Recently, I have several customers troubled in safe recover USB function during the ESD situation (or some other situations, like short dp/dm, ground dp/dm, etc). I designed the ESD detect and recovery process, but I met some sync problems between host controller driver (eg, ehci) and class driver (eg, mass storage). For example, when khubd tries to disconnect usb device, it will try to stop thread usb-storage, but usb-storage is waiting some transfers to finish, qTD and QH operation may be finished (usb_submit_urb does not return error), but no watchdog timer and completion interrupt are occurred. I have: esd_detect_process and esd_recovery_process at host controller driver. At esd_detect_porcess It will disable usb interrupt and judge ASE and PSE, etc. At esd_recovery_process: It needs to reset controller (usbcmd.rst, and toggle portsc.pp bit, etc) I would like to have some synchronization mechanism between usb_submit_urb or (ehci_urb_enqueue) and my esd_detect_process and esd_recovery_process. But still not find a safe one, eg, I still met khubd's status changes D problem described above. Any suggestions are appreciated, Thanks. -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How to safe recover USB driver from broken hardware situation
On Mon, 22 Apr 2013, Peter Chen wrote: Hi all, Recently, I have several customers troubled in safe recover USB function during the ESD situation (or some other situations, like short dp/dm, ground dp/dm, etc). I designed the ESD detect and recovery process, but I met some sync problems between host controller driver (eg, ehci) and class driver (eg, mass storage). For example, when khubd tries to disconnect usb device, it will try to stop thread usb-storage, but usb-storage is waiting some transfers to finish, qTD and QH operation may be finished (usb_submit_urb does not return error), but no watchdog timer and completion interrupt are occurred. I have: esd_detect_process and esd_recovery_process at host controller driver. At esd_detect_porcess It will disable usb interrupt and judge ASE and PSE, etc. At esd_recovery_process: It needs to reset controller (usbcmd.rst, and toggle portsc.pp bit, etc) I would like to have some synchronization mechanism between usb_submit_urb or (ehci_urb_enqueue) and my esd_detect_process and esd_recovery_process. But still not find a safe one, eg, I still met khubd's status changes D problem described above. Any suggestions are appreciated, Thanks. Your recovery process should not need to make all these changes to ehci-hcd. Simply carry out the same actions as the dead: statement label in ehci_irq() -- that is, do the same thing as if an interrupt occurred with the STS_FATAL bit set. That code is all properly synchronized. Then unbind the driver from the controller and rebind it. Rebinding will reset the controller. Alan Stern -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: How to safe recover USB driver from broken hardware situation
On Mon, Apr 22, 2013 at 11:26:05AM -0400, Alan Stern wrote: On Mon, 22 Apr 2013, Peter Chen wrote: Hi all, Recently, I have several customers troubled in safe recover USB function during the ESD situation (or some other situations, like short dp/dm, ground dp/dm, etc). I designed the ESD detect and recovery process, but I met some sync problems between host controller driver (eg, ehci) and class driver (eg, mass storage). For example, when khubd tries to disconnect usb device, it will try to stop thread usb-storage, but usb-storage is waiting some transfers to finish, qTD and QH operation may be finished (usb_submit_urb does not return error), but no watchdog timer and completion interrupt are occurred. I have: esd_detect_process and esd_recovery_process at host controller driver. At esd_detect_porcess It will disable usb interrupt and judge ASE and PSE, etc. At esd_recovery_process: It needs to reset controller (usbcmd.rst, and toggle portsc.pp bit, etc) I would like to have some synchronization mechanism between usb_submit_urb or (ehci_urb_enqueue) and my esd_detect_process and esd_recovery_process. But still not find a safe one, eg, I still met khubd's status changes D problem described above. Any suggestions are appreciated, Thanks. Your recovery process should not need to make all these changes to ehci-hcd. Simply carry out the same actions as the dead: statement label in ehci_irq() -- that is, do the same thing as if an interrupt occurred with the STS_FATAL bit set. That code is all properly synchronized. Sometimes, there are no STS_FATAL and STA_ERR when ESD occurs. So, you suggest do the same thing for STS_FATAL at my esd_recovery_process? Then unbind the driver from the controller and rebind it. Rebinding will reset the controller. You mean unbind the controller driver? Any existed API can be called? I can't do rmmod at that time. Thanks. -- Best Regards, Peter Chen -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
