Messages in this thread | | | Subject | Re: [PATCH v5 00/39] i.MX Media Driver | From | Steve Longerbeam <> | Date | Tue, 14 Mar 2017 10:02:26 -0700 |
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On 03/12/2017 03:10 PM, Mauro Carvalho Chehab wrote: > Em Sun, 12 Mar 2017 21:13:24 +0000 > Russell King - ARM Linux <linux@armlinux.org.uk> 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
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