From: Alan Stern <stern@rowland.harvard.edu>
To: Felipe Balbi <felipe.balbi@linux.intel.com>
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: Tue, 11 Jun 2019 09:53:03 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1906110950440.1535-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <875zpcfxfk.fsf@linux.intel.com>
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.
Alan Stern
next prev parent reply other threads:[~2019-06-11 13:53 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 [this message]
2019-06-12 6:58 ` Felipe Balbi
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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