From 8e4bff4cab0ddac6060645b0715210484d02ff40 Mon Sep 17 00:00:00 2001 From: Yuval Adam <_@yuv.al> Date: Wed, 30 Aug 2017 08:25:59 +0000 Subject: Initial file dump from open source release --- .../DocBook/media/v4l/vidioc-querycap.xml | 332 +++++++++++++++++++++ 1 file changed, 332 insertions(+) create mode 100644 Documentation/DocBook/media/v4l/vidioc-querycap.xml (limited to 'Documentation/DocBook/media/v4l/vidioc-querycap.xml') diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml b/Documentation/DocBook/media/v4l/vidioc-querycap.xml new file mode 100644 index 00000000..d5a3c97b --- /dev/null +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml @@ -0,0 +1,332 @@ + + + ioctl VIDIOC_QUERYCAP + &manvol; + + + + VIDIOC_QUERYCAP + Query device capabilities + + + + + + int ioctl + int fd + int request + struct v4l2_capability *argp + + + + + + Arguments + + + + fd + + &fd; + + + + request + + VIDIOC_QUERYCAP + + + + argp + + + + + + + + + Description + + All V4L2 devices support the +VIDIOC_QUERYCAP ioctl. It is used to identify +kernel devices compatible with this specification and to obtain +information about driver and hardware capabilities. The ioctl takes a +pointer to a &v4l2-capability; which is filled by the driver. When the +driver is not compatible with this specification the ioctl returns an +&EINVAL;. + + + struct <structname>v4l2_capability</structname> + + &cs-str; + + + __u8 + driver[16] + Name of the driver, a unique NUL-terminated +ASCII string. For example: "bttv". Driver specific applications can +use this information to verify the driver identity. It is also useful +to work around known bugs, or to identify drivers in error reports. +Storing strings in fixed sized arrays is bad +practice but unavoidable here. Drivers and applications should take +precautions to never read or write beyond the end of the array and to +make sure the strings are properly NUL-terminated. + + + __u8 + card[32] + Name of the device, a NUL-terminated UTF-8 string. +For example: "Yoyodyne TV/FM". One driver may support different brands +or models of video hardware. This information is intended for users, +for example in a menu of available devices. Since multiple TV cards of +the same brand may be installed which are supported by the same +driver, this name should be combined with the character device file +name (⪚ /dev/video2) or the +bus_info string to avoid +ambiguities. + + + __u8 + bus_info[32] + Location of the device in the system, a +NUL-terminated ASCII string. For example: "PCI:0000:05:06.0". This +information is intended for users, to distinguish multiple +identical devices. If no such information is available the field must +simply count the devices controlled by the driver ("platform:vivi-000"). +The bus_info must start with "PCI:" for PCI boards, "PCIe:" for PCI Express boards, +"usb-" for USB devices, "I2C:" for i2c devices, "ISA:" for ISA devices, +"parport" for parallel port devices and "platform:" for platform devices. + + + __u32 + version + Version number of the driver. +Starting on kernel 3.1, the version reported is provided per +V4L2 subsystem, following the same Kernel numberation scheme. However, it +should not always return the same version as the kernel, if, for example, +an stable or distribution-modified kernel uses the V4L2 stack from a +newer kernel. +The version number is formatted using the +KERNEL_VERSION() macro: + + + + +#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c)) + +__u32 version = KERNEL_VERSION(0, 8, 1); + +printf ("Version: %u.%u.%u\n", + (version >> 16) & 0xFF, + (version >> 8) & 0xFF, + version & 0xFF); + + + + __u32 + capabilities + Available capabilities of the physical device as a whole, see . The same physical device can export + multiple devices in /dev (e.g. /dev/videoX, /dev/vbiY and /dev/radioZ). + The capabilities field should contain a union + of all capabilities available around the several V4L2 devices exported + to userspace. + For all those devices the capabilities field + returns the same set of capabilities. This allows applications to open + just one of the devices (typically the video device) and discover whether + video, vbi and/or radio are also supported. + + + + __u32 + device_caps + Device capabilities of the opened device, see . Should contain the available capabilities + of that specific device node. So, for example, device_caps + of a radio device will only contain radio related capabilities and + no video or vbi capabilities. This field is only set if the capabilities + field contains the V4L2_CAP_DEVICE_CAPS capability. + Only the capabilities field can have the + V4L2_CAP_DEVICE_CAPS capability, device_caps + will never set V4L2_CAP_DEVICE_CAPS. + + + + __u32 + reserved[3] + Reserved for future extensions. Drivers must set +this array to zero. + + + +
+ + + Device Capabilities Flags + + &cs-def; + + + V4L2_CAP_VIDEO_CAPTURE + 0x00000001 + The device supports the single-planar API through the Video Capture interface. + + + V4L2_CAP_VIDEO_CAPTURE_MPLANE + 0x00001000 + The device supports the + multi-planar API through the + Video Capture interface. + + + V4L2_CAP_VIDEO_OUTPUT + 0x00000002 + The device supports the single-planar API through the Video Output interface. + + + V4L2_CAP_VIDEO_OUTPUT_MPLANE + 0x00002000 + The device supports the + multi-planar API through the + Video Output interface. + + + V4L2_CAP_VIDEO_M2M + 0x00004000 + The device supports the single-planar API through the + Video Memory-To-Memory interface. + + + V4L2_CAP_VIDEO_M2M_MPLANE + 0x00008000 + The device supports the + multi-planar API through the + Video Memory-To-Memory interface. + + + V4L2_CAP_VIDEO_OVERLAY + 0x00000004 + The device supports the Video Overlay interface. A video overlay device +typically stores captured images directly in the video memory of a +graphics card, with hardware clipping and scaling. + + + V4L2_CAP_VBI_CAPTURE + 0x00000010 + The device supports the Raw +VBI Capture interface, providing Teletext and Closed Caption +data. + + + V4L2_CAP_VBI_OUTPUT + 0x00000020 + The device supports the Raw VBI Output interface. + + + V4L2_CAP_SLICED_VBI_CAPTURE + 0x00000040 + The device supports the Sliced VBI Capture interface. + + + V4L2_CAP_SLICED_VBI_OUTPUT + 0x00000080 + The device supports the Sliced VBI Output interface. + + + V4L2_CAP_RDS_CAPTURE + 0x00000100 + The device supports the RDS capture interface. + + + V4L2_CAP_VIDEO_OUTPUT_OVERLAY + 0x00000200 + The device supports the Video +Output Overlay (OSD) interface. Unlike the Video +Overlay interface, this is a secondary function of video +output devices and overlays an image onto an outgoing video signal. +When the driver sets this flag, it must clear the +V4L2_CAP_VIDEO_OVERLAY flag and vice +versa.The &v4l2-framebuffer; lacks an +&v4l2-buf-type; field, therefore the type of overlay is implied by the +driver capabilities. + + + V4L2_CAP_HW_FREQ_SEEK + 0x00000400 + The device supports the &VIDIOC-S-HW-FREQ-SEEK; ioctl for +hardware frequency seeking. + + + V4L2_CAP_RDS_OUTPUT + 0x00000800 + The device supports the RDS output interface. + + + V4L2_CAP_TUNER + 0x00010000 + The device has some sort of tuner to +receive RF-modulated video signals. For more information about +tuner programming see +. + + + V4L2_CAP_AUDIO + 0x00020000 + The device has audio inputs or outputs. It may or +may not support audio recording or playback, in PCM or compressed +formats. PCM audio support must be implemented as ALSA or OSS +interface. For more information on audio inputs and outputs see . + + + V4L2_CAP_RADIO + 0x00040000 + This is a radio receiver. + + + V4L2_CAP_MODULATOR + 0x00080000 + The device has some sort of modulator to +emit RF-modulated video/audio signals. For more information about +modulator programming see +. + + + V4L2_CAP_READWRITE + 0x01000000 + The device supports the read() and/or write() +I/O methods. + + + V4L2_CAP_ASYNCIO + 0x02000000 + The device supports the asynchronous I/O methods. + + + V4L2_CAP_STREAMING + 0x04000000 + The device supports the streaming I/O method. + + + V4L2_CAP_DEVICE_CAPS + 0x80000000 + The driver fills the device_caps + field. This capability can only appear in the capabilities + field and never in the device_caps field. + + + +
+ + + + &return-value; + + -- cgit v1.3.1