From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30209C433E0 for ; Tue, 30 Jun 2020 12:02:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 15A6D20774 for ; Tue, 30 Jun 2020 12:02:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732746AbgF3MCJ (ORCPT ); Tue, 30 Jun 2020 08:02:09 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:52995 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729924AbgF3MCJ (ORCPT ); Tue, 30 Jun 2020 08:02:09 -0400 Received: from uno.localdomain (93-34-118-233.ip49.fastwebnet.it [93.34.118.233]) (Authenticated sender: jacopo@jmondi.org) by relay12.mail.gandi.net (Postfix) with ESMTPSA id B89EB200008; Tue, 30 Jun 2020 12:01:59 +0000 (UTC) Date: Tue, 30 Jun 2020 14:05:28 +0200 From: Jacopo Mondi To: Dafna Hirschfeld Cc: mchehab@kernel.org, sakari.ailus@linux.intel.com, hverkuil@xs4all.nl, laurent.pinchart@ideasonboard.com, roman.kovalivskyi@globallogic.com, dave.stevenson@raspberrypi.org, naush@raspberrypi.com, mrodin@de.adit-jv.com, hugues.fruchet@st.com, mripard@kernel.org, aford173@gmail.com, sudipi@jp.adit-jv.com, andrew_gabbasov@mentor.com, erosca@de.adit-jv.com, linux-media@vger.kernel.org, libcamera-devel@lists.libcamera.org, dafna Hirschfeld Subject: Re: [PATCH 20/25] media: ov5647: Program mode only if it has changed Message-ID: <20200630120528.xffvivfriblc6a2y@uno.localdomain> References: <20200623100815.10674-1-jacopo@jmondi.org> <20200623165550.45835-1-jacopo@jmondi.org> <80139e40-914f-c547-922f-91fe3f611202@collabora.com> <20200630074305.soctqoaqirfdnvv2@uno.localdomain> <20200630100651.ikjcazgbvoq2hab4@uno.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Dafna, On Tue, Jun 30, 2020 at 12:56:44PM +0200, Dafna Hirschfeld wrote: > > > On 30.06.20 12:06, Jacopo Mondi wrote: > > Hi Dafna, > > > > On Tue, Jun 30, 2020 at 11:32:12AM +0200, Dafna Hirschfeld wrote: > > > > > > > > > On 30.06.20 09:43, Jacopo Mondi wrote: > > > > Hi Dafna, > > > > > > > > On Mon, Jun 29, 2020 at 07:48:16PM +0200, Dafna Hirschfeld wrote: > > > > > > > > > > > > > > > On 23.06.20 18:55, Jacopo Mondi wrote: > > > > > > Store in the driver structure a pointer to the currently applied mode > > > > > > and program a new one at s_stream(1) time only if it has changed. > > > > > > > > > > Hi, > > > > > I think this can be more readably implemented with a 'is_streaming' boolean > > > > > field. > > > > > > > > How would you like to use an 'is_streaming' flag to decide if the > > > > sensor mode has to be updated ? > > > > > > since 'current_mode' is set to NULL upon `ov5647_stream_off` > > > and you return from 'ov5647_set_stream' immediately if 'mode == current_mode' > > > it seem very similar to returning immediately from 'ov5647_set_stream' if the > > > device is currently streaming. > > > > No, the code returns immediately from ov5647_set_mode() if mode == > > current_mode. The modes comparison makes sure the sensor is not > > reprogrammed if the mode hasn't changed. The remaning part of > > s_stream() is executed regardless of the mode configuration. Am I > > missing some part of the picture ? > > > > > > > > But actually in this patch it seems to be possible to change the mode > > > while streaming, if the callbacks are executed: > > > > > > s_stream(1) > > > s_fmt > > > s_stream(1) > > > > > > which is maybe a bug? > > > > The new format is stored in sensor->mode, and applied at the next > > s_stream(1) operation if it differs from the already programmed one, > > at least, this is how it is intended to work, have you found any > > failing s_stream/set_fmt/s_stream which could be caused by a bug ? > > What I meant is that there could be valid sequence of calls > > s_stream(enable=1) > s_fmt > s_stream(enable=1) > > For example if two video devices are connected to the sensor and they > stream simultaneously. There was a discussion about adding a code to the core I'm not sure it is possible, given that the subdev has a single source pad > to follow the s_stream callback and call it only if the subdev is not streaming > but currently subdevs should support it themselves. > Oh, so you're concerned about the fact userspace can call s_stream(1) twice consecutively! it's indipendent from s_ftm if I got your point. In this case a flag to control if the device is streaming already should help, yes, I overlooked that indeed. Thanks j > > Thanks, > Dafna > > > > > Thanks > > j > > > > > > Thanks, > > > Dafna > > > > > > > > > > > Thanks > > > > j > > > > > > > > > > > > > > > > > > Thanks, > > > > > Dafna > > > > > > > > > > > > > > > > > Signed-off-by: Jacopo Mondi > > > > > > --- > > > > > > drivers/media/i2c/ov5647.c | 16 +++++++++++++++- > > > > > > 1 file changed, 15 insertions(+), 1 deletion(-) > > > > > > > > > > > > diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c > > > > > > index 39e320f321bd8..ac114269e1c73 100644 > > > > > > --- a/drivers/media/i2c/ov5647.c > > > > > > +++ b/drivers/media/i2c/ov5647.c > > > > > > @@ -96,6 +96,7 @@ struct ov5647 { > > > > > > bool clock_ncont; > > > > > > struct v4l2_ctrl_handler ctrls; > > > > > > struct ov5647_mode *mode; > > > > > > + struct ov5647_mode *current_mode; > > > > > > }; > > > > > > static inline struct ov5647 *to_sensor(struct v4l2_subdev *sd) > > > > > > @@ -750,9 +751,13 @@ static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel) > > > > > > static int ov5647_set_mode(struct v4l2_subdev *sd) > > > > > > { > > > > > > struct i2c_client *client = v4l2_get_subdevdata(sd); > > > > > > + struct ov5647 *sensor = to_sensor(sd); > > > > > > u8 resetval, rdval; > > > > > > int ret; > > > > > > + if (sensor->mode == sensor->current_mode) > > > > > > + return 0; > > > > > > + > > > > > > ret = ov5647_read(sd, OV5647_SW_STANDBY, &rdval); > > > > > > if (ret < 0) > > > > > > return ret; > > > > > > @@ -778,6 +783,8 @@ static int ov5647_set_mode(struct v4l2_subdev *sd) > > > > > > return ret; > > > > > > } > > > > > > + sensor->current_mode = sensor->mode; > > > > > > + > > > > > > return 0; > > > > > > } > > > > > > @@ -816,6 +823,7 @@ static int ov5647_stream_on(struct v4l2_subdev *sd) > > > > > > static int ov5647_stream_off(struct v4l2_subdev *sd) > > > > > > { > > > > > > + struct ov5647 *sensor = to_sensor(sd); > > > > > > int ret; > > > > > > ret = ov5647_write(sd, OV5647_REG_MIPI_CTRL00, MIPI_CTRL00_CLOCK_LANE_GATE | > > > > > > @@ -827,7 +835,13 @@ static int ov5647_stream_off(struct v4l2_subdev *sd) > > > > > > if (ret < 0) > > > > > > return ret; > > > > > > - return ov5647_write(sd, OV5640_REG_PAD_OUT, 0x01); > > > > > > + ret = ov5647_write(sd, OV5640_REG_PAD_OUT, 0x01); > > > > > > + if (ret < 0) > > > > > > + return ret; > > > > > > + > > > > > > + sensor->current_mode = NULL; > > > > > > + > > > > > > + return 0; > > > > > > } > > > > > > static int set_sw_standby(struct v4l2_subdev *sd, bool standby) > > > > > >