From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from osg.samsung.com ([64.30.133.232]:42767 "EHLO osg.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753254AbeDMOIK (ORCPT ); Fri, 13 Apr 2018 10:08:10 -0400 Date: Fri, 13 Apr 2018 11:08:03 -0300 From: Mauro Carvalho Chehab To: Sean Young Cc: Linux Media Mailing List , Mauro Carvalho Chehab , Patrice Chotard , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 15/17] media: st_rc: Don't stay on an IRQ handler forever Message-ID: <20180413110803.0599eb2a@vento.lan> In-Reply-To: <20180413132052.37fudkaxltvwc46v@gofer.mess.org> References: <16b1993cde965edc096f0833091002dd05d4da7f.1523546545.git.mchehab@s-opensource.com> <20180412222132.z7g5enhin2uodbk7@gofer.mess.org> <20180413060646.25b8a19d@vento.lan> <20180413094005.wudyd2y5efaeimg3@gofer.mess.org> <20180413070050.10d0de84@vento.lan> <20180413132052.37fudkaxltvwc46v@gofer.mess.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Em Fri, 13 Apr 2018 14:20:52 +0100 Sean Young escreveu: > On Fri, Apr 13, 2018 at 07:00:50AM -0300, Mauro Carvalho Chehab wrote: > > Yeah, we could limit it to run only 512 times (or some other reasonable > > quantity), but in order to do that, we need to be sure that, on each read(), > > the FIFO will shift - e. g. no risk of needing to do more than one read > > to get the next element. That would work if the FIFO is implemented via > > flip-flops. But if it is implemented via some slow memory, or if the > > shift logic is implemented via some software on a micro-controller, it > > may need a few interactions to get the next value. > > > > Without knowing about the hardware implementation, I'd say that setting > > a max time for the whole FIFO interaction is safer. > > Ok. If the 10ms timeout is reached, there really is a problem; should we > report an error in this case? Maybe, but then it should likely warn only once. Thanks, Mauro