[RFC | PATCH] move device-specific private data out of tuner struct

[mkrufky at linuxtv.org (Michael Krufky)]

Markus Rechberger wrote:
> On 5/29/07, Mauro Carvalho Chehab <mchehab at infradead.org> wrote:
>> Em Ter, 2007-05-29 ?s 16:38 -0400, Michael Krufky escreveu:
>> > As it stands currently, all device-specific data for analog tuner
>> > drivers are stored in the main tuner struct.  This is a potential
>> waste
>> > of memory for tuner drivers that do not utilize all of these
>> structures.
>> >
>> > Up until now, as the needs of the drivers have changed, a developer
>> > would issue an RFC to explain what he needs to add to the tuner struct
>> > in order to handle the necessary change for the driver in question.
>> > With these private structures moved out of the main tuner struct, such
>> > changes in the future would only affect the specific tuner driver.
>> >
>> > I have written a driver for the Philips / NXP TDA18271 silicon tuner.
>> > This driver needs to maintain a snapshot of the register values in
>> > memory -- this would be a waste of space for the other tuner
>> drivers, as
>> > this space would only be needed for the tda18271.  Since this
>> memory is
>> > only needed for the TDA18271, it makes sense that it should be
>> stored in
>> > a private area specific to the TDA18271, only.
>> >
>> > The attached patch allocates these private structures on an as-needed
>> > basis, within the object code for that specific tuner, rather than
>> > globally inside the main tuner structure.  This change could also be
>> > considered as a cleanup / overhaul, which brings the tuner.ko module
>> > closer to an object-oriented design.
>> >
>> > Would anybody have any issues with this patch, if it were applied?
>>
>> The patch looks sane and it is really a good idea. Of course, it should
>> be tested on all touched tuners.
>>
>
> this is a good change yes.
>
> Markus
Mauro & Markus,

Thanks for the feedback -- I've already tested this on the tda8290 +
8275, and on a tin can tuner (LG-H064F) using a tda9887 ...  The only
tuner driver affected by this change that hasn't been tested yet is
mt20xx.  Does anybody have a card using mt20xx that can test this?

It should be safe to push it into the master branch and -mm , to achieve
sufficient testing before the 2.6.23 merge window opens, which should be
months away.

For now, I've pushed the changeset to this tree:

http://linuxtv.org/hg/~mkrufky/tuner

- tuner: Move device-specific private data out of tuner struct

 drivers/media/video/mt20xx.c     |   33 +++++++++---
 drivers/media/video/tda8290.c    |  105
++++++++++++++++++++++++---------------
 drivers/media/video/tda9887.c    |   37 ++++++++-----
 drivers/media/video/tuner-core.c |   10 +++
 include/media/tuner.h            |   13 ----
 5 files changed, 124 insertions(+), 74 deletions(-)

Cheers,

Mike