The addition of jump label support in dynamic_debug caused an unexpected
warning in exactly one file in the kernel:
drivers/media/dvb-frontends/cxd2841er.c: In function 'cxd2841er_tune_tc':
include/linux/dynamic_debug.h:134:3: error: 'carrier_offset' may be used uninitialized in this function [-Werror=maybe-uninitialized]
__dynamic_dev_dbg(&descriptor, dev, fmt, \
^~~~~~~~~~~~~~~~~
drivers/media/dvb-frontends/cxd2841er.c:3177:11: note: 'carrier_offset' was declared here
int ret, carrier_offset;
^~~~~~~~~~~~~~
The problem seems to be that the compiler gets confused by the extra
conditionals in static_branch_unlikely, to the point where it can no
longer keep track of which branches have already been taken, and it
doesn't realize that this variable is now always initialized when it
gets used.
I have done lots of randconfig kernel builds and could not find any
other file with this behavior, so I assume it's a rare enough glitch
that we don't need to change the jump label support but instead just
work around the warning in the driver.
To achieve that, I'm moving the check for the return value into the
switch() statement, which is an obvious transformation, but is enough to
un-confuse the compiler here. The resulting code is not as nice to
read, but at least we retain the behavior of warning if it gets changed
to actually access an uninitialized carrier offset value in the future.
Link: http://lkml.kernel.org/r/20160713204342.1221511-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Abylay Ospan <aospan@netup.ru>
Cc: Sergey Kozlov <serjk@netup.ru>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Jason Baron <jbaron@akamai.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now driver returns correct values for DVB-C:
SNR (in dB)
[mchehab@s-opensource.com: fix a new function to be static]
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
now driver returns correct values for DVB-C:
BER (post_bit_count and post_bit_error values)
UCB (count of uncorrected errors)
also, some code cleanup was done - checkpatch.pl now is happy
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
DVB-C should use cxd2841er_read_agc_gain_c() to get the gain. The same
function is used for all DVB-C annex delivery systems.
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The scale for ISDB-T was wrong too: it was inverted, and
on a relative scale.
Use a linear interpolation to make it look better.
The formula was empirically determined, using 3 frequencies
(175 MHz, 410 MHz and 800 MHz), measuring from -50dBm to
-12dBm in steps of 0.5dB.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Instead of using a relative frequency range, calibrate it to
show the results in dB. The callibration was done getting
samples with a signal generated from -50dBm to -12dBm,
incremented in steps of 0.5 dB, using 3 frequencies:
175 MHz, 410 MHz and 800 MHz. The modulated signal was
using QAM64, and it was used a linear interpolation of all
the results.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Currently, there's no stats for DVB-C. Let's at least return
signal strength. The scale is different than on DVB-T, so let's
use a relative scale, for now.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
What userspace expects is to receive both bit_error and bit_count
counters. So, instead of doing the division at the Kernel,
return the counters for userspace to handle it the way it
wants.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The current code will expose a zero value if one of the stats is
not available, but this is not what userspace expects. Instead,
if something goes wrong on providing some stats, it should be
changing the scale to FE_SCALE_NOT_AVAILABLE.
So, change the logic to do the right thing.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
cxd2841er_read_agc_gain_c added to obtain signal strength.
signal strength now relay on AGC value.
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
The signal strength value is reversed: the bigger the number,
the weaker is the signal.
Fix the logic and present it in dBm. Please notice that the
dBm measure is actually an estimation, as the ratio is not
fully linear. It also varies with the frequency.
Yet, the estimation should be good enough for programs like
Kaffeine to indicate when the signal is good or bad.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
It is a good idea to measure the signal strength while
tuning, as this helps to identify if the antenna is ok.
Also, such measure helps to identify the quality of the
signal.
Do some changes to enable it before signal lock. While
here, optimize the code to only initialize the stats
length once, and make sure that, just after set_frontend,
any reading for the stats that depends on lock to return
FE_SCALE_NOT_AVAILABLE.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
correct is CXD2841ER and CXD2854ER
incorrect was CXD2441ER and CXD2454ER
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
now when new tuning parameters specified demod should retune.
Also ISDB-T frequency offset calculation added
(cxd2841er_get_carrier_offset_i).
While here, fix re-tune for DVB-C Annex A, using the desired
bandwidth, instead of using 8MHz.
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Avoid error message:
cxd2841er_read_status_s(): invalid state 1
Always force demod to shutdown state before initializing
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
CXD2854ER is identical to CXD2841ER except ISDB-T/S added.
New method 'cxd2841er_attach_i' is added
xtal frequency now configurable. Available options:
20.5MHz, 24MHz, 41MHz
Signed-off-by: Abylay Ospan <aospan@netup.ru>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Instead of using the DTV properties cache directly, pass the get
frontend data as an argument. For now, everything should remain
the same, but the next patch will prevent get_frontend to
affect the global cache.
This is needed because several drivers don't care enough to only
change the properties if locked. Due to that, calling
G_PROPERTY before locking on those drivers will make them to
never lock. Ok, those drivers are crap and should never be
merged like that, but the core should not rely that the drivers
would be doing the right thing.
Reviewed-by: Michael Ira Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
The Linux stack is short; we need to be able to count the number
of bytes used at stack on each function. So, we don't like to
use variable-length arrays, as complained by smatch:
drivers/media/dvb-frontends/cxd2841er.c:205:19: warning: Variable length array is used.
The max usecase of the driver seems to be 15 bytes + 1 for the
register.
So, let's be safe and allocate 17 bytes for the write buffer.
This should be enough to cover all cases. If not, let's print
an error message.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
drivers/media/dvb-frontends/cxd2841er.c:992:5: warning: no previous prototype for 'cxd2841er_get_carrier_offset_t2' [-Wmissing-prototypes]
int cxd2841er_get_carrier_offset_t2(
^
drivers/media/dvb-frontends/cxd2841er.c:1032:5: warning: no previous prototype for 'cxd2841er_get_carrier_offset_c' [-Wmissing-prototypes]
int cxd2841er_get_carrier_offset_c(
^
drivers/media/dvb-frontends/cxd2841er.c:1360:5: warning: no previous prototype for 'cxd2841er_read_snr_t2' [-Wmissing-prototypes]
int cxd2841er_read_snr_t2(struct cxd2841er_priv *priv, u32 *snr)
^
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
