From patchwork Fri Aug 24 15:09:40 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Timo Kokkonen X-Patchwork-Id: 1371661 Return-Path: X-Original-To: patchwork-linux-media@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id A86CFDF28C for ; Fri, 24 Aug 2012 15:10:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752060Ab2HXPJ4 (ORCPT ); Fri, 24 Aug 2012 11:09:56 -0400 Received: from mta-out.inet.fi ([195.156.147.13]:59023 "EHLO jenni1.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753103Ab2HXPJu (ORCPT ); Fri, 24 Aug 2012 11:09:50 -0400 Received: from itanic.dhcp.inet.fi (80.223.243.31) by jenni1.inet.fi (8.5.140.03) id 502AD34B00899EDB; Fri, 24 Aug 2012 18:09:48 +0300 From: Timo Kokkonen To: linux-omap@vger.kernel.org, linux-media@vger.kernel.org Subject: [PATCHv2 2/8] ir-rx51: Handle signals properly Date: Fri, 24 Aug 2012 18:09:40 +0300 Message-Id: <1345820986-4597-3-git-send-email-timo.t.kokkonen@iki.fi> X-Mailer: git-send-email 1.7.12 In-Reply-To: <1345820986-4597-1-git-send-email-timo.t.kokkonen@iki.fi> References: <1345820986-4597-1-git-send-email-timo.t.kokkonen@iki.fi> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The lirc-dev expects the ir-code to be transmitted when the write call returns back to the user space. We should not leave TX ongoing no matter what is the reason we return to the user space. Easiest solution for that is to simply remove interruptible sleeps. The first wait_event_interruptible is thus replaced with return -EBUSY in case there is still ongoing transfer. This should suffice as the concept of sending multiple codes in parallel does not make sense. The second wait_event_interruptible call is replaced with wait_even_timeout with a fixed and safe timeout that should prevent the process from getting stuck in kernel for too long. Also, from now on we will force the TX to stop before we return from write call. If the TX happened to time out for some reason, we should not leave the HW transmitting anything. Signed-off-by: Timo Kokkonen --- drivers/media/rc/ir-rx51.c | 39 ++++++++++++++++++++++++++++----------- 1 file changed, 28 insertions(+), 11 deletions(-) diff --git a/drivers/media/rc/ir-rx51.c b/drivers/media/rc/ir-rx51.c index 9487dd3..e2db94e 100644 --- a/drivers/media/rc/ir-rx51.c +++ b/drivers/media/rc/ir-rx51.c @@ -74,6 +74,19 @@ static void lirc_rx51_off(struct lirc_rx51 *lirc_rx51) OMAP_TIMER_TRIGGER_NONE); } +static void lirc_rx51_stop_tx(struct lirc_rx51 *lirc_rx51) +{ + if (lirc_rx51->wbuf_index < 0) + return; + + lirc_rx51_off(lirc_rx51); + lirc_rx51->wbuf_index = -1; + omap_dm_timer_stop(lirc_rx51->pwm_timer); + omap_dm_timer_stop(lirc_rx51->pulse_timer); + omap_dm_timer_set_int_enable(lirc_rx51->pulse_timer, 0); + wake_up(&lirc_rx51->wqueue); +} + static int init_timing_params(struct lirc_rx51 *lirc_rx51) { u32 load, match; @@ -160,13 +173,7 @@ static irqreturn_t lirc_rx51_interrupt_handler(int irq, void *ptr) return IRQ_HANDLED; end: - /* Stop TX here */ - lirc_rx51_off(lirc_rx51); - lirc_rx51->wbuf_index = -1; - omap_dm_timer_stop(lirc_rx51->pwm_timer); - omap_dm_timer_stop(lirc_rx51->pulse_timer); - omap_dm_timer_set_int_enable(lirc_rx51->pulse_timer, 0); - wake_up_interruptible(&lirc_rx51->wqueue); + lirc_rx51_stop_tx(lirc_rx51); return IRQ_HANDLED; } @@ -246,8 +253,9 @@ static ssize_t lirc_rx51_write(struct file *file, const char *buf, if ((count > WBUF_LEN) || (count % 2 == 0)) return -EINVAL; - /* Wait any pending transfers to finish */ - wait_event_interruptible(lirc_rx51->wqueue, lirc_rx51->wbuf_index < 0); + /* We can have only one transmit at a time */ + if (lirc_rx51->wbuf_index >= 0) + return -EBUSY; if (copy_from_user(lirc_rx51->wbuf, buf, n)) return -EFAULT; @@ -273,9 +281,18 @@ static ssize_t lirc_rx51_write(struct file *file, const char *buf, /* * Don't return back to the userspace until the transfer has - * finished + * finished. However, we wish to not spend any more than 500ms + * in kernel. No IR code TX should ever take that long. + */ + i = wait_event_timeout(lirc_rx51->wqueue, lirc_rx51->wbuf_index < 0, + HZ / 2); + + /* + * Ensure transmitting has really stopped, even if the timers + * went mad or something else happened that caused it still + * sending out something. */ - wait_event_interruptible(lirc_rx51->wqueue, lirc_rx51->wbuf_index < 0); + lirc_rx51_stop_tx(lirc_rx51); /* We can sleep again */ lirc_rx51->pdata->set_max_mpu_wakeup_lat(lirc_rx51->dev, -1);