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From: Mark Lord <kernel@teksavvy.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Philippe De Muyter <phdm@macqel.be>, Greg KH <greg@kroah.com>,
	Tejun Heo <tj@kernel.org>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
	linux-ide@vger.kernel.org, Greg Kroah-Hartman <gregkh@suse.de>,
	linux-usb@vger.kernel.org
Subject: Re: XT-PIC interrupts blocked by usbserial ? [Was Re: Intel ICH9M bug : sata unusable with usbserial]
Date: Thu, 03 Mar 2011 16:48:35 -0500	[thread overview]
Message-ID: <4D700CB3.10101@teksavvy.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1103031502100.1669-100000@iolanthe.rowland.org>

On 11-03-03 03:11 PM, Alan Stern wrote:
> On Thu, 3 Mar 2011, Mark Lord wrote:
> 
>> Okay, dug out a UHCI 1.1 spec, and the indication from there
>> is that uhci_irq() can return IRQ_HANDLED in some cases where IRQ_NONE
>> is more appropriate.
> 
> What cases are those?
> 
>> Also, it is not masking the "Reserved" bits from the status register.
>> Presumably most implementations "read zero" for those bits,
>> but perhaps not all do.
> 
> Perhaps not, but I've never come across one that does.  This
> essentially amounts to saying that the only reasons a UHCI controller
> generates an interrupt request are the documented ones.
> 
> Suppose the driver did mask out the reserved bits and return IRQ_NONE 
> when none of the defined bits were set.  An implementation that did set 
> one of the reserved bits would then create an interrupt storm.

You mean, like, the "error -71" storms that I *still* get from time
to time, ever since the early 2.6.2x kernels?

Yeah, perhaps.

Cheers

  reply	other threads:[~2011-03-03 21:48 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-28 14:01 Intel ICH9M bug : sata unusable with usbserial Philippe De Muyter
2011-02-28 15:05 ` Alan Cox
2011-02-28 15:16   ` Tejun Heo
2011-02-28 17:05     ` Philippe De Muyter
2011-02-28 17:36       ` Tejun Heo
2011-02-28 19:21         ` Philippe De Muyter
     [not found]         ` <20110228173634.GA23008-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2011-02-28 19:27           ` Greg KH
2011-03-01 12:34             ` Philippe De Muyter
2011-03-01 14:16               ` Greg KH
     [not found]                 ` <20110301141627.GB12881-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2011-03-01 15:00                   ` Philippe De Muyter
     [not found]                     ` <20110301150018.GA17827-NqYOdiUDesgPnqCj3zZnUQ@public.gmane.org>
2011-03-02 13:34                       ` Mark Lord
     [not found]                         ` <4D6E477A.9020401-R6A+fiHC8nRWk0Htik3J/w@public.gmane.org>
2011-03-03 14:58                           ` XT-PIC interrupts blocked by usbserial ? [Was Re: Intel ICH9M bug : sata unusable with usbserial] Philippe De Muyter
2011-03-03 15:23                             ` Sergei Shtylyov
     [not found]                               ` <4D6FB260.6010402-hkdhdckH98+B+jHODAdFcQ@public.gmane.org>
2011-03-04 14:24                                 ` Philippe De Muyter
2011-03-03 18:10                             ` Mark Lord
2011-03-03 18:20                               ` Greg KH
2011-03-04 14:29                               ` Philippe De Muyter
     [not found]                               ` <4D6FD982.2050308-R6A+fiHC8nRWk0Htik3J/w@public.gmane.org>
2011-03-04 14:56                                 ` Philippe De Muyter
2011-03-03 18:20                             ` Mark Lord
2011-03-03 19:06                               ` Alan Stern
2011-03-03 19:39                                 ` Mark Lord
     [not found]                                   ` <4D6FEE56.4080006-R6A+fiHC8nRWk0Htik3J/w@public.gmane.org>
2011-03-03 19:51                                     ` Mark Lord
2011-03-03 20:11                                       ` Alan Stern
2011-03-03 21:48                                         ` Mark Lord [this message]
2011-03-03 21:56                                           ` Alan Stern
2011-03-04  1:53                                       ` Robert Hancock

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