Hello Ralph Metzler,
The patch 43dd07f758d8: "[media] DRX-K: Initial check-in" from Jul 3,
2011, leads to the following warning:
drivers/media/dvb/frontends/drxk_hard.c:2980 ADCSynchronization()
warn: suspicious bitop condition
2977 status = read16(state, IQM_AF_CLKNEG__A, &clkNeg);
2978 if (status < 0)
2979 goto error;
2980 if ((clkNeg | IQM_AF_CLKNEG_CLKNEGDATA__M) ==
2981 IQM_AF_CLKNEG_CLKNEGDATA_CLK_ADC_DATA_POS) {
IQM_AF_CLKNEG_CLKNEGDATA__M is 2.
IQM_AF_CLKNEG_CLKNEGDATA_CLK_ADC_DATA_POS is 0.
So this condition can never be true.
2982 clkNeg &= (~(IQM_AF_CLKNEG_CLKNEGDATA__M));
2983 clkNeg |=
2984 IQM_AF_CLKNEG_CLKNEGDATA_CLK_ADC_DATA_NEG;
2985 } else {
2986 clkNeg &= (~(IQM_AF_CLKNEG_CLKNEGDATA__M));
2987 clkNeg |=
2988 IQM_AF_CLKNEG_CLKNEGDATA_CLK_ADC_DATA_POS;
clkNeg |= 0; <-- doesn't make much sense to the unenlightened.
2989 }
I wrote a Smatch thing to find places that do x |= 0 inspired by the
above oddity and it finds several other places which do that:
drivers/media/dvb/frontends/drxk_hard.c:2525 GetQAMSignalToNoise() info: why not propagate 'status' from read16() instead of -22?
drivers/media/dvb/frontends/drxk_hard.c:2980 ADCSynchronization() warn: suspicious bitop condition
drivers/media/dvb/frontends/drxk_hard.c:2988 ADCSynchronization() warn: x |= 0
drivers/media/dvb/frontends/drxk_hard.c:3833 SetDVBT() warn: x |= 0
drivers/media/dvb/frontends/drxk_hard.c:3847 SetDVBT() warn: x |= 0
drivers/media/dvb/frontends/drxk_hard.c:3888 SetDVBT() warn: x |= 0
drivers/media/dvb/frontends/drxk_hard.c:3915 SetDVBT() warn: x |= 0
drivers/media/dvb/frontends/drxk_hard.c:3931 SetDVBT() warn: x |= 0
regards,
dan carpenter
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