[pvrusb2] New driver snapshot: pvrusb2-mci-20090315

[Xavier Gnata]

Hi Mike,

Would you say that this new intermediate layer is a good thing?
What is the purpose of this?
Does it really avoid a lot a code duplication?

Anyhow thanks  for this release :)

Xavier

> A new pvrusqy thqt this method sb2 driver snapshot is available.  The driver changes are:
>
>   (+) Various miscellaneous tweaks to preserve reasonably correct
>       compilation for older kernels (test compiled back to 2.6.12.3).
>   
>   (+) Implement and enable composite and s-video inputs for OnAir
>       devices.
>
>   (+) Remove ancient IVTV_IOC_G_CODEC and IVTV_IOC_S_CODEC ioctl
>       functions.  These are very very old, were non-standard, and were
>       only present to keep MythTV happy (their implementation did
>       nothing except to report success).  That was long ago; no recent
>       versions of MythTV should require this anymore.
>
>   (+) MAJOR: Implement a new client modules layer, based upon the
>       v4l2-subdev framework.  Note that this is only active in the
>       standalone driver when building against v4l-dvb or in a kernel
>       that is 2.6.29 or later.  The v4l-dvb core has a new mechanism
>       known as "v4l2-subdev".  This is a whole new method for finding,
>       attaching to, and communicating with all the various chip-level
>       drivers.  This is the "official" way of controlling all the
>       "sub-drivers" now.  This is also expected to be required
>       starting with kernel 2.6.30 (i.e. support for the old i2c
>       specific mechanism will be removed).  The pvrusb2 standalone
>       driver for now still has the old method implemented alongside
>       the new one - compile time options select which method to build
>       depending on the environment (i.e. kernel version).  So
>       backwards compatibility for now is not affected and the driver
>       should _in theory_ continue to work all the way back to 2.6.12
>       (conditioned of course on the other various things mentioned in
>       the setup documentation).  But at some point in the future, I
>       expect it will become too cumbersome to keep both methods
>       working, at which point I will remove the old method and the
>       standalone driver will then no longer directly support kernels
>       older than approximately 2.6.29 (the point when the v4l2-subdev
>       mechanism first became workable and resident in the mainline
>       kernel).
>
>   (+) Fix build so that V4LDIR trick works again for building against
>       v4l-dvb.
>
>   (+) Use usb_make_path (where possible) to report device bus
>       location.  This produces a more stable result than what had been
>       done before.
>
> In addition to those driver changes, I've combed through the online
> documentation and fixed various errors, updated various things.  I've
> added new information about Gotview and OnAir support (the support in
> question isn't new but the documentation was wrong or misleading).  I
> have also added notes and references to the OnAir firmware, both
> available now at isely.net and also at Autumnwave's site.
>
> Note that the "major" change above is in preparation for the 2.6.30
> kernel, where that logic will be required in order for the driver to
> continue working correctly.  It's a complete replacement for the
> driver's control logic for handling all the "chip-level" drivers it
> must deal with.  The required new v4l-dvb framework (a.k.a.
> "v4l2-subdev") for this appears in 2.6.29, so the driver build is
> configured to switch on the new implementation at that kernel version
> (and correspondingly disable the old implementation).  The short
> summary of this is that you won't be affected by that "major" change
> at all until you try to build the driver in kernel 2.6.29 or later.
>
> The outward changes for this release are actually fairly small.  But
> the new control framework itself involves a lot of new code (which is
> ifdef'ed out until you try 2.6.29 or later).  It's a lot of stuff for
> (hopefully!) very little visible change.
>
> As usual, the pvrusb2 web site can be found at:
>
>   http://www.isely.net/pvrusb2/pvrusb2.html
>
>   -Mike
>
>