From: Vojtech Pavlik <vojtech@suse.cz>
To: Pete Zaitcev <zaitcev@redhat.com>
Cc: cijoml@volny.cz, linux-kernel@vger.kernel.org,
linux-usb-deve@lists.sourceforge.net
Subject: Re: for USB guys - strange things in dmesg
Date: Tue, 11 Jan 2005 15:21:35 +0100 [thread overview]
Message-ID: <20050111142135.GA3729@ucw.cz> (raw)
In-Reply-To: <20050108150003.4adfdd7e@lembas.zaitcev.lan>
On Sat, Jan 08, 2005 at 03:00:03PM -0800, Pete Zaitcev wrote:
> On Thu, 30 Dec 2004 21:13:00 +0100, Michal Semler <cijoml@volny.cz> wrote:
>
> > when inserting my Bluetooth dongle into USB port, I get into dmesg this:
> > Bluetooth: RFCOMM ver 1.4
> > Bluetooth: RFCOMM socket layer initialized
> > Bluetooth: RFCOMM TTY layer initialized
> > drivers/usb/input/hid-core.c: input irq status -84 received
>
> >[.... LONG flood of the same messages ....]
>
> > drivers/usb/input/hid-core.c: input irq status -84 received
> > usb 3-1: USB disconnect, address 3
> > drivers/usb/input/hid-core.c: input irq status -84 received
> > drivers/usb/input/hid-core.c: can't resubmit intr, 0000:00:1d.2-1/input1, status -19
> > usb 3-1: new full speed USB device using uhci_hcd and address 4
> > Bluetooth: HCI USB driver ver 2.7
>
> What happens here is that the device disconnects itself during or after
> it's initialized.
>
> Once the HC hardware detects the disconnect, future URBs will end with
> -84 error. However, the HID driver does not do anything about it.
> It continues to attempt to resubmit until the khubd does its processing
> and enters its disconnect method. In extreme cases, it is possible to
> have this submit-and-error-and-repeat loop to monopolize the CPU and
> prevent khubd from working ever, thus effectively locking up the box.
> Fortunately, in 2.6 kernel we standardized error codes, and thus drivers
> like hid can rely on -84 meaning a disconnect and not something else.
> In such case, hid has to stop resubmitting before its disconnect method
> is executed.
-84 is, according to documentation, -EILSEQ, and means "a CRC error",
that shouldn't normally happen and "indicates hardware problems such as
bad devices (including firmware) or cables".
I'm getting -84 on disconnect now, too, which suggests that uhci-hcd
might be using incorrect error code here.
Looking at uhci-hcd, it reports -EILSEQ in case there is a timeout on
the bus talking to the device. This can happen due to a disconnect, but
the HC should notice the disconnect I believe and return the right error
code.
Disconnects (-ESHUTDOWN) are already handled by hid-core.c
> This is relevant to all drivers which submit interrupt URBs. One driver
> which does it correctly is mct_u232 (surprisingly enough), so the code
> can be taken from there.
--
Vojtech Pavlik
SuSE Labs, SuSE CR
next prev parent reply other threads:[~2005-01-11 14:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.1104438600.3923.linux-kernel2news@redhat.com>
2005-01-08 23:00 ` for USB guys - strange things in dmesg Pete Zaitcev
2005-01-11 14:21 ` Vojtech Pavlik [this message]
2005-01-11 16:37 ` Vojtech Pavlik
2005-01-09 16:48 David Brownell
-- strict thread matches above, loose matches on Subject: below --
2004-12-30 20:13 Michal Semler
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