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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4209ECD5BCD for ; Tue, 19 Sep 2023 15:21:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233000AbjISPVT (ORCPT ); Tue, 19 Sep 2023 11:21:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233098AbjISPVS (ORCPT ); Tue, 19 Sep 2023 11:21:18 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B794FB for ; Tue, 19 Sep 2023 08:21:12 -0700 (PDT) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 411ECB53; Tue, 19 Sep 2023 17:19:34 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1695136774; bh=RBjEl68UqG4JpiJ12BcL1TDdC/O0FwpCqm9PFRnFTJU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RatCAIXfKsNjiWg9jXg4D4REdLP9EOzu/eV31peLlByRQ3w9KnG+pnZIiqAv3GO2u qqmUe3D6g2Dd3Laz9J5CLH+2j1YK9egtRgKRc6sILMNznCFdJvSEPp63pmv0uuoAAo PjfEHjrtUnczaZNLjQWUtNM+VxGEP66uMyZDv+j4= Date: Tue, 19 Sep 2023 18:21:23 +0300 From: Laurent Pinchart To: Sakari Ailus Cc: linux-media@vger.kernel.org, Tianshu Qiu , Bingbu Cao , Tomi Valkeinen , Jacopo Mondi , Rui Miguel Silva , Martin Kepplinger Subject: Re: [PATCH v3 11/12] media: v4l: subdev: Print debug information on frame descriptor Message-ID: <20230919152123.GA18426@pendragon.ideasonboard.com> References: <20230919121728.126781-1-sakari.ailus@linux.intel.com> <20230919121728.126781-12-sakari.ailus@linux.intel.com> <20230919133248.GD1505@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Sep 19, 2023 at 02:49:29PM +0000, Sakari Ailus wrote: > Hi Laurent, > > On Tue, Sep 19, 2023 at 04:32:48PM +0300, Laurent Pinchart wrote: > > Hi Sakari, > > > > Thank you for the patch. > > > > On Tue, Sep 19, 2023 at 03:17:27PM +0300, Sakari Ailus wrote: > > > Print debug level information on returned frame descriptors. > > > > > > Signed-off-by: Sakari Ailus > > > --- > > > drivers/media/v4l2-core/v4l2-subdev.c | 32 ++++++++++++++++++++++++++- > > > 1 file changed, 31 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c > > > index 7b087be3ff4f..504ca625b2bd 100644 > > > --- a/drivers/media/v4l2-core/v4l2-subdev.c > > > +++ b/drivers/media/v4l2-core/v4l2-subdev.c > > > @@ -15,6 +15,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > #include > > > #include > > > #include > > > @@ -309,9 +310,38 @@ static int call_set_selection(struct v4l2_subdev *sd, > > > static int call_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad, > > > struct v4l2_mbus_frame_desc *fd) > > > { > > > + unsigned int i; > > > + int ret; > > > + > > > memset(fd, 0, sizeof(*fd)); > > > > > > - return sd->ops->pad->get_frame_desc(sd, pad, fd); > > > + ret = sd->ops->pad->get_frame_desc(sd, pad, fd); > > > + if (ret) > > > + return ret; > > > + > > > + dev_dbg(sd->dev, "Frame descriptor on pad %u, type %s\n", pad, > > > + fd->type == V4L2_MBUS_FRAME_DESC_TYPE_PARALLEL ? "parallel" : > > > + fd->type == V4L2_MBUS_FRAME_DESC_TYPE_CSI2 ? "CSI-2" : > > > + "unknown"); > > > + > > > + for (i = 0; i < fd->num_entries; i++) { > > > + struct v4l2_mbus_frame_desc_entry *entry = &fd->entry[i]; > > > + char buf[20] = ""; > > > > Should this be sized for the worst case ? The vc and dt should not be > > large, but a buffer overflow on the stack in debug code if a subdev > > returns an incorrect value would be bad. > > 17 should be enough but it's not useful to use a size not divisible by 4 in > practice here. 18 with the terminating 0. But indeed, it's large enough as vc and dt are u8. I'm just a bit worried we're opening the door to hard to debug problems if we later change the vc and dt types. > > > + > > > + if (fd->type == V4L2_MBUS_FRAME_DESC_TYPE_CSI2) > > > + snprintf(buf, sizeof(buf), ", vc %u, dt 0x%2.2x", > > > > 0x%02x would be one character shorter ;-) Same below. > > It would be, but I prefer the above notation as it's more generic. Out of curiosity, how so ? > > > + entry->bus.csi2.vc, entry->bus.csi2.dt); > > > + > > > + dev_dbg(sd->dev, > > > + "\tstream %u, code 0x%4.4x, lenght %u, flags%s%s%s\n", > > > > s/lenght/length/ > > Thanks, I'll fix this. > > > > + entry->stream, entry->pixelcode, entry->length, > > > + entry->flags & V4L2_MBUS_FRAME_DESC_FL_LEN_MAX ? > > > + " LEN_MAX" : "", > > > + entry->flags & V4L2_MBUS_FRAME_DESC_FL_BLOB ? > > > + " BLOB" : "", buf); > > > > If no flags are set, you will get something like > > > > stream 0, code 0x1234, length ..., flags, vc 0, dt 0x2a > > > > Maybe printing the hex value for the flags would be simpler and clearer > > ? > > How about adding the numerical value in addition to the strings? > > The use of these flags is rare though. I could just remove the strings, > too. Up to you. -- Regards, Laurent Pinchart