Messages in this thread | | | From | David Brownell <> | Subject | Re: [linux-usb-devel] [PATCH] Ohci-hcd: fix endless loop | Date | Fri, 26 Nov 2004 08:38:10 -0800 |
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On Thursday 25 November 2004 10:17, Colin Leroy wrote: > Hi, > > Following patch fixes an endless loop that happens after having > slept and resumed my iBook with a linux-wlan-ng controller plugged in, > removed the stick and plugged it back (getting "IRQ lossage" message).
The infinite loop means that something trashed the stack, yes?
The "limit-- < -1000" test below should never be able to succeed unless the previous "limit-- == 0" test got trashed by having something obliterate the stack. Possibly the driver for that WLAN adapter. Once that happens, all kinds of things will misbehave...
If you got the "IRQ INTR_SF lossage" diagnostic, there's clearly some problem with IRQ handling after the resume ... is the iBook firmware (or hardware) doing wierd stuff so that the normal PCI IRQ calls stopped working?
And for that matter, "limit" is unsigned, so you must be getting (and ignoring) some compiler warnings too.
This is not a good patch; not accepted.
- Dave
> Signed-off-by: Colin Leroy <colin@colino.net> > --- a/drivers/usb/host/ohci-hcd.c 2004-11-25 19:00:25.000000000 +0100 > +++ b/drivers/usb/host/ohci-hcd.c 2004-11-25 19:08:59.000000000 +0100 > @@ -375,6 +375,11 @@ > spin_unlock_irqrestore (&ohci->lock, flags); > set_current_state (TASK_UNINTERRUPTIBLE); > schedule_timeout (1); > + if (limit-- < -1000) { > + ohci_warn (ohci, "Couldn't recover\n"); > + ohci_restart(ohci); > + goto bail; > + } > goto rescan; > case ED_IDLE: /* fully unlinked */ > if (list_empty (&ed->td_list)) { > @@ -396,6 +401,7 @@ > dev->ep [epnum] = NULL; > done: > spin_unlock_irqrestore (&ohci->lock, flags); > +bail: > return; > } > > > > ------------------------------------------------------- > SF email is sponsored by - The IT Product Guide > Read honest & candid reviews on hundreds of IT Products from real users. > Discover which products truly live up to the hype. Start reading now. > http://productguide.itmanagersjournal.com/ > _______________________________________________ > linux-usb-devel@lists.sourceforge.net > To unsubscribe, use the last form field at: > https://lists.sourceforge.net/lists/listinfo/linux-usb-devel > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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