Hi Hans,
Thanks for the patch.
On Friday 07 September 2012 15:29:05 Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> During the 2012 Media Workshop it was decided that bus_info as returned
> by VIDIOC_QUERYCAP can no longer be empty. It should be a unique identifier,
> and empty strings are obviously not unique.
>
> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> ---
> Documentation/DocBook/media/v4l/vidioc-querycap.xml | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> b/Documentation/DocBook/media/v4l/vidioc-querycap.xml index
> f33dd74..d5b1248 100644
> --- a/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> +++ b/Documentation/DocBook/media/v4l/vidioc-querycap.xml
> @@ -90,11 +90,17 @@ ambiguities.</entry>
> <entry>__u8</entry>
> <entry><structfield>bus_info</structfield>[32]</entry>
> <entry>Location of the device in the system, a
> -NUL-terminated ASCII string. For example: "PCI Slot 4". This
> +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 may
> -simply count the devices controlled by the driver, or contain the
> -empty string (<structfield>bus_info</structfield>[0] = 0).<!-- XXX
> pci_dev->slot_name example --></entry>
> +identical devices. If no such information is available the field must
> +simply count the devices controlled by the driver ("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 and
> +"parport" for parallel port devices.
What about being a bit more precise than that ? We could specify what API
drivers must use to fill the bus_info field. For instance, for USB devices,
usb_make_path() is currently used by most drivers (which, by the way, doesn't
return a string that starts with "USB:").
> +For devices without a bus it should start with the driver name, optionally
> +followed by "-" and an index if multiple instances of the device as
> possible.
> +Many platform devices can have only one instance, so in that case bus_info
> +is identical to the <structfield>driver</structfield> field.</entry> </row>
> <row>
> <entry>__u32</entry>
--
Regards,
Laurent Pinchart
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