Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752845AbdCNRCs (ORCPT ); Tue, 14 Mar 2017 13:02:48 -0400 Received: from relay1.mentorg.com ([192.94.38.131]:45972 "EHLO relay1.mentorg.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751188AbdCNRCq (ORCPT ); Tue, 14 Mar 2017 13:02:46 -0400 Subject: Re: [PATCH v5 00/39] i.MX Media Driver To: Mauro Carvalho Chehab , Russell King - ARM Linux References: <1489121599-23206-1-git-send-email-steve_longerbeam@mentor.com> <20170312194700.GR21222@n2100.armlinux.org.uk> <20170312175923.6ad86dff@vento.lan> <20170312211324.GW21222@n2100.armlinux.org.uk> <20170312191002.5f0a2cff@vento.lan> CC: Steve Longerbeam , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , From: Steve Longerbeam Message-ID: <06038465-5634-3f69-521d-3f2a7d14afde@mentor.com> Date: Tue, 14 Mar 2017 10:02:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20170312191002.5f0a2cff@vento.lan> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: svr-orw-mbx-04.mgc.mentorg.com (147.34.90.204) To svr-orw-mbx-02.mgc.mentorg.com (147.34.90.202) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4019 Lines: 94 On 03/12/2017 03:10 PM, Mauro Carvalho Chehab wrote: > Em Sun, 12 Mar 2017 21:13:24 +0000 > Russell King - ARM Linux escreveu: > >> On Sun, Mar 12, 2017 at 05:59:28PM -0300, Mauro Carvalho Chehab wrote: >>> Yet, udev/systemd has some rules that provide an unique name for V4L >>> devices at /lib/udev/rules.d/60-persistent-v4l.rules. Basically, it >>> runs a small application (v4l_id) with creates a persistent symling >>> using rules like this: >>> >>> KERNEL=="video*", ENV{ID_SERIAL}=="?*", SYMLINK+="v4l/by-id/$env{ID_BUS}-$env{ID_SERIAL}-video-index$attr{index}" >>> >>> Those names are stored at /dev/v4l/by-path. >> This doesn't help: >> >> $ ls -Al /dev/v4l/by-id/ >> total 0 >> lrwxrwxrwx 1 root root 13 Mar 12 19:54 usb-Sonix_Technology_Co.__Ltd._USB_2.0_Camera-video-index0 -> ../../video10 >> $ ls -Al /dev/v4l/by-path/ >> total 0 >> lrwxrwxrwx 1 root root 12 Mar 12 19:54 platform-2040000.vpu-video-index0 -> ../../video0 >> lrwxrwxrwx 1 root root 12 Mar 12 19:54 platform-2040000.vpu-video-index1 -> ../../video1 >> lrwxrwxrwx 1 root root 12 Mar 12 20:53 platform-capture-subsystem-video-index0 -> ../../video2 >> lrwxrwxrwx 1 root root 12 Mar 12 20:53 platform-capture-subsystem-video-index1 -> ../../video3 >> lrwxrwxrwx 1 root root 12 Mar 12 20:53 platform-capture-subsystem-video-index2 -> ../../video4 >> lrwxrwxrwx 1 root root 12 Mar 12 20:53 platform-capture-subsystem-video-index3 -> ../../video5 >> lrwxrwxrwx 1 root root 12 Mar 12 20:53 platform-capture-subsystem-video-index4 -> ../../video6 >> lrwxrwxrwx 1 root root 12 Mar 12 20:53 platform-capture-subsystem-video-index5 -> ../../video7 >> lrwxrwxrwx 1 root root 12 Mar 12 20:53 platform-capture-subsystem-video-index6 -> ../../video8 >> lrwxrwxrwx 1 root root 12 Mar 12 20:53 platform-capture-subsystem-video-index7 -> ../../video9 >> lrwxrwxrwx 1 root root 13 Mar 12 19:54 platform-ci_hdrc.0-usb-0:1:1.0-video-index0 -> ../../video10 >> >> The problem is the "platform-capture-subsystem-video-index" entries. >> These themselves change order. For instance, I now have: >> >> - entity 72: ipu1_csi0 capture (1 pad, 1 link) >> type Node subtype V4L flags 0 >> device node name /dev/video6 >> >> which means it's platform-capture-subsystem-video-index4. Before, it >> was platform-capture-subsystem-video-index2. > That's a driver problem. v4l_id gets information to build the persistent > name from the result of VIDIOC_QUERYCAP. > > In the case of Exynos gsc driver, for example, the information is here: > > static int gsc_m2m_querycap(struct file *file, void *fh, > struct v4l2_capability *cap) > { > struct gsc_ctx *ctx = fh_to_ctx(fh); > struct gsc_dev *gsc = ctx->gsc_dev; > > strlcpy(cap->driver, GSC_MODULE_NAME, sizeof(cap->driver)); > strlcpy(cap->card, GSC_MODULE_NAME " gscaler", sizeof(cap->card)); > snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s", > dev_name(&gsc->pdev->dev)); > cap->device_caps = V4L2_CAP_STREAMING | V4L2_CAP_VIDEO_M2M_MPLANE | > V4L2_CAP_VIDEO_CAPTURE_MPLANE | V4L2_CAP_VIDEO_OUTPUT_MPLANE; > > cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS; > return 0; > } > > See that the bus_info there is filled with: > > snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s", dev_name(&gsc->pdev->dev)); > > From the output you printed, it seems that the i.MX6 is just doing: > snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:"); > for some devices. imx6 is setting bus_info string on all capture devices as: snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s", dev_name(priv->dev)); dev_name(priv->dev) is the device name of the attached subdev. So the bus_info string, at least for attached CSI subdevs, should be "platform:imx-ipuv3-csi". Maybe there is something else missing, I haven't had a chance to look at this yet. Steve > > If you change the i.MX6 driver to do the same, you'll likely be able to > have unique names there too. > > Regards, > Mauro