From: Felipe Balbi <felipe.balbi@linux.intel.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Mathias Nyman <mathias.nyman@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
David Howells <dhowells@redhat.com>,
viro@zeniv.linux.org.uk, linux-usb@vger.kernel.org,
raven@themaw.net, linux-fsdevel@vger.kernel.org,
linux-api@vger.kernel.org, linux-block@vger.kernel.org,
keyrings@vger.kernel.org, linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 09/10] usb: Add USB subsystem notifications [ver #3]
Date: Wed, 12 Jun 2019 09:58:33 +0300 [thread overview]
Message-ID: <87h88v1e92.fsf@linux.intel.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1906110950440.1535-100000@iolanthe.rowland.org>
Hi,
Alan Stern <stern@rowland.harvard.edu> writes:
> On Tue, 11 Jun 2019, Felipe Balbi wrote:
>
>> >> >> > So for "severe" issues, yes, we should do this, but perhaps not for all
>> >> >> > of the "normal" things we see when a device is yanked out of the system
>> >> >> > and the like.
>> >> >>
>> >> >> Then what counts as a "severe" issue? Anything besides enumeration
>> >> >> failure?
>> >> >
>> >> > Not that I can think of at the moment, other than the other recently
>> >> > added KOBJ_CHANGE issue. I'm sure we have other "hard failure" issues
>> >> > in the USB stack that people will want exposed over time.
>> >>
>> >> From an XHCI standpoint, Transaction Errors might be one thing. They
>> >> happen rarely and are a strong indication that the bus itself is
>> >> bad. Either bad cable, misbehaving PHYs, improper power management, etc.
>> >
>> > Don't you also get transaction errors if the user unplugs a device in
>> > the middle of a transfer? That's not the sort of thing we want to sent
>> > notifications about.
>>
>> Mathias, do we get Transaction Error if user removes cable during a
>> transfer? I thought we would just get Port Status Change with CC bit
>> cleared, no?
>
> Even if xHCI doesn't give Transaction Errors when a cable is unplugged
> during a transfer, other host controllers do. Sometimes quite a lot --
> they continue to occur until the kernel polls the parent hub's
> interrupt ep and learns that the port is disconnected, which can take
> up to 250 ms.
my comment was specific about XHCI. It even started with "From an XHCI
standpoint" :-)
--
balbi
next prev parent reply other threads:[~2019-06-12 6:58 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 9:41 [RFC][PATCH 00/10] Mount, FS, Block and Keyrings notifications [ver #3] David Howells
2019-06-06 9:42 ` [PATCH 01/10] security: Override creds in __fput() with last fputter's creds " David Howells
2019-06-06 14:57 ` Andy Lutomirski
2019-06-06 15:06 ` David Howells
2019-06-06 17:18 ` Andy Lutomirski
2019-06-06 19:09 ` Casey Schaufler
2019-06-06 19:34 ` Andy Lutomirski
2019-06-06 9:42 ` [PATCH 02/10] General notification queue with user mmap()'able ring buffer " David Howells
2019-06-06 9:42 ` [PATCH 03/10] keys: Add a notification facility " David Howells
2019-06-06 9:42 ` [PATCH 04/10] vfs: Add a mount-notification " David Howells
2019-06-06 9:42 ` [PATCH 05/10] vfs: Add superblock notifications " David Howells
2019-06-06 9:42 ` [PATCH 06/10] fsinfo: Export superblock notification counter " David Howells
2019-06-06 9:43 ` [PATCH 07/10] Add a general, global device notification watch list " David Howells
2019-06-06 9:43 ` [PATCH 08/10] block: Add block layer notifications " David Howells
2019-06-06 9:43 ` [PATCH 09/10] usb: Add USB subsystem " David Howells
2019-06-06 14:24 ` Alan Stern
2019-06-06 14:33 ` Greg Kroah-Hartman
2019-06-06 14:55 ` Alan Stern
2019-06-06 15:31 ` Greg Kroah-Hartman
2019-06-07 6:40 ` Felipe Balbi
2019-06-07 14:01 ` Alan Stern
2019-06-11 6:28 ` Felipe Balbi
2019-06-11 13:53 ` Alan Stern
2019-06-12 6:58 ` Felipe Balbi [this message]
2019-06-06 9:43 ` [PATCH 10/10] Add sample notification program " David Howells
2019-06-06 21:21 ` Eugeniu Rosca
2019-06-06 22:52 ` David Howells
2019-06-07 14:37 ` David Howells
2019-06-06 12:32 ` [RFC][PATCH 00/10] Mount, FS, Block and Keyrings notifications " Stephen Smalley
2019-06-06 13:16 ` David Howells
2019-06-06 14:05 ` Stephen Smalley
2019-06-06 16:43 ` Casey Schaufler
2019-06-06 17:11 ` Andy Lutomirski
2019-06-06 18:33 ` Casey Schaufler
2019-06-06 18:51 ` Andy Lutomirski
2019-06-06 17:16 ` Stephen Smalley
2019-06-06 18:56 ` Casey Schaufler
2019-06-06 19:54 ` Andy Lutomirski
2019-06-06 21:17 ` David Howells
2019-06-06 21:54 ` Andy Lutomirski
2019-06-06 22:38 ` David Howells
2019-06-06 22:42 ` Andy Lutomirski
2019-06-06 22:50 ` David Howells
2019-06-06 14:34 ` Christian Brauner
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