On Fri September 7 2012 22:00:33 Sylwester Nawrocki wrote:
> On 09/07/2012 03:29 PM, 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>
>
> Reviewed-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
>
> > ---
> > 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.
> > +For devices without a bus it should start with the driver name, optionally
>
> Most, if not all, devices are on some sort of bus. What would be an example
> of a device "without a bus" ?
Virtual devices like vivi and platform devices. Or is there some sort of
platform bus?
> Could we just be saying here "For other devices" instead of "For devices
> without a bus", or something similar ?
Well, I'd like for any device on a bus to have a consistent naming convention
so we can guarantee that bus_info is always unique.
Regards,
Hans
>
> > +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,
> Sylwester
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