On 05/19/2011 04:43 PM, RafaÅ MiÅecki wrote:
2011/5/19 Larry Finger<Larry.Finger@xxxxxxxxxxxx>:When cross-compiling the 2.6.39 wireless-testing source using GCC version (SUSE Linux) 4.3.2 [gcc-4_3-branch revision 141291] on an x86_64 system, the following warning is issued: CC [M] drivers/net/wireless/b43/phy_n.o drivers/net/wireless/b43/phy_n.c: In function âb43_nphy_cal_tx_iq_loâ: drivers/net/wireless/b43/phy_n.c:3096: warning: âlastâ may be used uninitialized in this function A quick look at the code shows that the warning is bogus and a gcc bug, but to ensure clean compilation for all users, mark the offending variable as uninitialized.Did you check for both "last" usages on this function? From my quick review it seems "last" is set in case of 1) mphase_cal_phase_id> 2 xor 2) b43_nphy_tx_tone returning success I'm not so sure if this patch is correct.
My analysis is as follows: "last" is created in line 3096. In line 3256, it is set by the statement "last = (dev->phy.rev < 3) ? 6 : 7;". In line 3258 and 3300, it is tested for equality with "nphy->mphase_cal_phase_id". As there is no path around line 3256, it seems to me that last must be assigned a value at 3256 and the warning is bogus.
The call in line 3154 to b43_nphy_tx_tone is "error = b43_nphy_tx_tone(dev, freq, 250, true, false);" and does not access last.
If this patch is not correct, then last must be initialized to zero and the older compiler is correct and the newer ones are buggy for not reporting the problem.
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