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While having tda18271 module set with debug=17 (cal & info prints) and cal=0 (delay calibration process until first use) - I discovered that during the calibration process, if the frequency test for 69750000 returned a bcal of 0 (see tda18721-fe.c in tda18271_powerscan func) that the tuner wouldn't be able to pickup any of the frequencies in the range (all the other frequencies bands returned bcal=1). I spent some time going over the code and the NXP's tda18271 spec (ver.4 of it i think) and adding a lot of debug prints and walking/stepping through the calibration process. I found that when the powerscan fails to find a frequency, the rf calibration is not run and the default value is supposed to be used in its place (pulled from the RF_CAL_map table) - but something was getting goofed up there. Now, my c coding skills are very rusty, but i think root of the problem is a signedness issue with the math operation for calculating the rf_a1 and rf_a2 values in tda18271_rf_tracking_filters_init func, which results in values like 20648 for rf_a1 (when it should probably have a value like 0, or so slightly negative that it should be zero - this bad value for rf_a1 would in turn makes the approx calc within tda18271c2_rf_tracking_filters_correction go out of whack). The simplest solution i found was to explicitly convert the signedness of the denominator to avoid the implicit conversion. The values placed into the u32 rf_freq array should never exceed about 900mhz, so i think the s32 max value shouldn't be an issue in this case. I've tested it out a little, and even when i get a bcal=0 with the modified code, the default calibration value gets used, rf_a1 is zero, and the tuner seems to lock on the stream and mythtv seems to play it fine. Signed-off-by: Seth Barry <seth@cyberseth.com> Signed-off-by: Michael Krufky <mkrufky@kernellabs.com> CC: stable@kernel.org Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com> |
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| .. | ||
| tuners | ||
| ir-functions.c | ||
| ir-keymaps.c | ||
| Kconfig | ||
| Makefile | ||
| saa7146_core.c | ||
| saa7146_fops.c | ||
| saa7146_hlp.c | ||
| saa7146_i2c.c | ||
| saa7146_vbi.c | ||
| saa7146_video.c | ||