From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from galahad.ideasonboard.com ([185.26.127.97]:48202 "EHLO galahad.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754747AbbIIIni (ORCPT ); Wed, 9 Sep 2015 04:43:38 -0400 From: Laurent Pinchart To: Hans de Goede Cc: Alan Stern , Mian Yousaf Kaukab , linux-media@vger.kernel.org, mchehab@osg.samsung.com, linux-usb@vger.kernel.org Subject: Re: [PATCH v1] media: uvcvideo: handle urb completion in a work queue Date: Wed, 09 Sep 2015 11:43:36 +0300 Message-ID: <1866316.khDarOHzbX@avalon> In-Reply-To: <55EFEE14.5050100@redhat.com> References: <55EFEE14.5050100@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-media-owner@vger.kernel.org List-ID: On Wednesday 09 September 2015 10:30:12 Hans de Goede wrote: > On 08-09-15 16:36, Alan Stern wrote: > > On Tue, 8 Sep 2015, Hans de Goede wrote: > >> On 09/07/2015 06:23 PM, Mian Yousaf Kaukab wrote: > >>> urb completion callback is executed in host controllers interrupt > >>> context. To keep preempt disable time short, add urbs to a list on > >>> completion and schedule work to process the list. > >>> > >>> Moreover, save timestamp and sof number in the urb completion callback > >>> to avoid any delays. > >> > >> Erm, I thought that we had already moved to using threaded interrupt > >> handling for the urb completion a while (1-2 years ?) back. Is this then > >> still needed ? > > > > We moved to handling URB completions in a tasklet, not a threaded > > handler. > > Right. > > > (Similar idea, though.) And the change was made in only one > > or two HCDs, not in all of them. > > Ah, I was under the impression this was a core change, not a per > hcd change. Instead of fixing the issue in the uvcvideo driver, would it then make more sense to fix it in the remaining hcd drivers ? -- Regards, Laurent Pinchart