Date: Fri, 1 Apr 2005 23:17:53 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: Sebastien B <sebastien.b@swissinfo.org> Cc: freebsd-usb@freebsd.org Subject: Re: panic: uhci_abort_xfer: not in process context (was Re: uplcom / ucom problems on RELENG_5) Message-ID: <200504012317.54966.hselasky@c2i.net> In-Reply-To: <200504012144.11468.sebastien.b@swissinfo.org> References: <6.2.1.2.0.20050329222822.04f7c500@64.7.153.2> <200503311946.23151.hselasky@c2i.net> <200504012144.11468.sebastien.b@swissinfo.org>
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On Friday 01 April 2005 21:44, Sebastien B wrote: > > When one is designing a driver, it is very convenient if USB-transfers > > can be stopped/started from the callback of another USB-transfer. > > I have run exactly into the same trouble by calling usbd_bulk_transfer() > from a software interrupt handler (scheduled to run from the context of the > start procedure of a network interface in order to send packets). The > kernel panics with "ehci_abort_xfer: not in process context" a few while > after the transfer. Is it the same problem ? Is a software interrupt > handler unsuitable for the abort xfer function ? How can I fix it, by using > a task queue instead of a software interrupt handler ? > Regards, > Sebastien With the existing USB driver you cannot call usbd_abort_pipe() nor usbd_bulk_transfer(), from an interrupt context or callback, because those functions will sleep. You can call usbd_transfer(), if the transfer is not synchronous. But the panic is a bug, and it might be because the ehci_abort_xfer() function is called from the transfer's timeout function? The solution is to use DELAY() instead of tsleep() and usb_delay_ms(). Yours --HPS
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