On 4/14/20 2:56 PM, Dan Carpenter wrote:
On Sun, Apr 12, 2020 at 04:34:08PM +0300, Ivan Safonov wrote:
Remove function rtw_modular64 as all it does is call do_div.
This is wrong. Macro do_div(x, y) change first argument x, but
rtw_modular64(x, y) preserve it.
+ tsf = pmlmeext->TSFValue - do_div(pmlmeext->TSFValue,
(pmlmeinfo->bcn_interval*1024)) - 1024; /* us */
rounddown(pmlmeext->TSFValue, pmlmeinfo->bcn_interval * 1024) - 1024
is a better replacement for
You're absolutely correct that the patch is buggy, but I'm not sure that
rounddown() is what we want.
rtw_modular64() took the MOD of x. So it should be something like:
tsf = pmlmeext->TSFValue - (pmlmeext->TSFValue %
(pmlmeinfo->bcn_interval * 1024)) - 1024; /* us */
But what the heck is that even??? If pmlmeinfo->bcn_interval is zero
or one then the subtraction ends up giving us a negative.
regards,
dan carpenter
1. pmlmeext->TSFValue can not be negative, because it is uint64_t;
2. pmlmeext->TSFValue is cyclic value:
https://en.wikipedia.org/wiki/Timing_synchronization_function ;
3. (rounddown(a, b)) is equal to (a - a % b) by definition.
Ivan Safonov.
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