From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
To: Julius Werner <jwerner@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
Alan Stern <stern@rowland.harvard.edu>,
Sarah Sharp <sarah.a.sharp@linux.intel.com>,
Benson Leung <bleung@chromium.org>,
Vincent Palatin <vpalatin@chromium.org>,
Duncan Laurie <dlaurie@chromium.org>
Subject: Re: [PATCH] usb: hub: Clear Port Reset Change during init/resume
Date: Wed, 16 Oct 2013 01:32:06 +0400 [thread overview]
Message-ID: <525DB456.1040006@cogentembedded.com> (raw)
In-Reply-To: <1381872227-24757-1-git-send-email-jwerner@chromium.org>
Hello.
On 10/16/2013 01:23 AM, Julius Werner wrote:
> This patch adds the Port Reset Change flag to the set of bits that are
> preemptively cleared on init/resume of a hub. In theory this bit should
> never be set unexpectedly... in practice it can still happen if BIOS,
> SMM or ACPI code plays around with USB devices without cleaning up
> correctly. This is especially dangerous for XHCI root hubs, which don't
> generate any more Port Status Change Events until all change bits are
> cleared, so this is a good precaution to have (similar to how it's
> already done for the Warm Port Reset Change flag).
> Signed-off-by: Julius Werner <jwerner@chromium.org>
> ---
> drivers/usb/core/hub.c | 5 +++++
> 1 file changed, 5 insertions(+)
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index e6b682c..c9ef5b8 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1130,6 +1130,11 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
> usb_clear_port_feature(hub->hdev, port1,
> USB_PORT_FEAT_C_ENABLE);
> }
> + if ((portchange & USB_PORT_STAT_C_RESET)) {
Hm, why these double parens?
WBR, Sergei
next prev parent reply other threads:[~2013-10-15 21:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-15 21:23 [PATCH] usb: hub: Clear Port Reset Change during init/resume Julius Werner
2013-10-15 21:32 ` Sergei Shtylyov [this message]
2013-10-16 0:42 ` Julius Werner
2013-10-16 0:45 ` [PATCH v2] " Julius Werner
2013-10-16 14:40 ` Alan Stern
2013-10-16 23:57 ` Sarah Sharp
2013-10-17 0:05 ` Benson Leung
2013-10-17 0:53 ` Julius Werner
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