In the media drivers, the v4l2 core knows about all submodules
and calls into them from a common function. However this cannot
work if the modules that get called are loadable and the
core is built-in. In that case we get
drivers/built-in.o: In function `set_type':
drivers/media/v4l2-core/tuner-core.c:301: undefined reference to `tea5767_attach'
drivers/media/v4l2-core/tuner-core.c:307: undefined reference to `tea5761_attach'
drivers/media/v4l2-core/tuner-core.c:349: undefined reference to `tda9887_attach'
drivers/media/v4l2-core/tuner-core.c:405: undefined reference to `xc4000_attach'
This was working previously, until the IS_ENABLED() macro was used
to replace the construct like
#if defined(CONFIG_DVB_CX24110) || (defined(CONFIG_DVB_CX24110_MODULE) && defined(MODULE))
with the difference that the new code no longer checks whether it is being
built as a loadable module itself.
To fix this, this new patch adds an 'IS_REACHABLE' macro, which evaluates
true in exactly the condition that was used previously. The downside
of this is that this trades an obvious link error for a more subtle
runtime failure, but it is clear that the change that introduced the
link error was unintentional and it seems better to revert it for
now. Also, a similar change was originally created by Trent Piepho
and then reverted by teh change to the IS_ENABLED macro.
Ideally Kconfig would be used to avoid the case of a broken dependency,
or the code restructured in a way to turn around the dependency, but either
way would require much larger changes here.
Fixes: 7b34be71db ("[media] use IS_ENABLED() macro")
See-also: c5dec9fb24 ("V4L/DVB (4751): Fix DBV_FE_CUSTOMISE for card drivers compiled into kernel")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Exporting multiple symbols don't work as it causes compilation
breakages, due to the way dvb_attach() works.
This were reported several times, like:
drivers/built-in.o: In function `cxusb_dualdig4_rev2_tuner_attach':
>> cxusb.c:(.text+0x27d4b5): undefined reference to `dib7000p_get_i2c_master'
drivers/built-in.o: In function `dib7070_set_param_override':
cxusb.c:(.text+0x27d5a5): undefined reference to `dib0070_wbd_offset'
>> cxusb.c:(.text+0x27d5be): undefined reference to `dib7000p_set_wbd_ref'
drivers/built-in.o: In function `dib7070_tuner_reset':
>> cxusb.c:(.text+0x27d5f9): undefined reference to `dib7000p_set_gpio'
drivers/built-in.o: In function `cxusb_dualdig4_rev2_frontend_attach':
>> cxusb.c:(.text+0x27df5c): undefined reference to `dib7000p_i2c_enumeration'
In this specific report:
CONFIG_DVB_USB_CXUSB=y
CONFIG_DVB_DIB7000P=m
But the same type of bug can happen if:
CONFIG_DVB_DIB7000P=m
and one of the bridge drivers is compiled builtin (cxusb, cx23885-dvb
and/or dib0700).
As a bonus, dib7000p won't be loaded anymore if the device uses
a different frontend, reducing the memory footprint.
Tested with Hauppauge Nova-TD (2 frontends).
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Well, what we call as "foo_attach" is the method that should
be called by the dvb_attach() macro.
It should be noticed that the name "dvb_attach" is really a
bad name and don't express what it does.
dvb_attach() basically does three things, if the frontend is
compiled as a module:
- It lookups for the module that it is known to have the
given symbol name and requests such module;
- It increments the module usage (anonymously - so lsmod
doesn't print who loaded the module);
- after loading the module, it runs the function associated
with the dynamic symbol.
When compiled as builtin, it just calls the function given to it.
As dvb_attach() increments refcount, it can't be (easily)
called more than once for the same module, or the kernel
will deny to remove the module, because refcount will never
be zeroed.
In other words, the function name given to dvb_attach()
should be one single symbol that will always be called
before any other function on that module to be used.
For almost all DVB frontends, there's just one function.
However, the dib7000p initialization can require up to 3
functions to be called:
- dib7000p_get_i2c_master;
- dib7000p_i2c_enumeration;
- dib7000p_init (before this patch dib7000_attach).
(plus a bunch of other functions that the bridge driver will
need to call).
As we need to get rid of all those direct calls, because they
cause compilation breakages when bridge is builtin and
frontend is module, we'll need to add a new function that
will be the first one to be called, whatever initialization
is needed.
So, let's rename the function that probes and init the hardware
to dib7000p_init.
A latter patch will add a new dib7000p_attach that will be
used as originally conceived by dvb_attach() way.
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
The intend of this patch is to improve the support of the dib7000p. It is
now possible to set the minimum value for the AGC1. Also, the driver takes
into account the frequency offset introduced in the tuned frequency.
Signed-off-by: Olivier Grenie <olivier.grenie@parrot.com>
Signed-off-by: Patrick Boettcher <patrick.boettcher@parrot.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Raise the DVB frontends one level up, as the intention is to remove
the drivers/media/dvb directory.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
