Hi! > On Tue, Apr 11, 2023 at 11:52:20AM -0400, William Breathitt Gray wrote: > > commit 4aa3b75c74603c3374877d5fd18ad9cc3a9a62ed upstream. > > > > The Counter (CNTR) register is 24 bits wide, but we can have an > > effective 25-bit count value by setting bit 24 to the XOR of the Borrow > > flag and Carry flag. The flags can be read from the FLAG register, but a > > race condition exists: the Borrow flag and Carry flag are instantaneous > > and could change by the time the count value is read from the CNTR > > register. > > Since the race condition could result in an incorrect 25-bit count > > value, remove support for 25-bit count values from this driver. I believe usual solution is to read the carry, read the counter, and read the carry again. If old_carry = new_carry, we are pretty sure we did not hit the race, and can use 25 bit value. Best regards, Pavel -- People of Russia, stop Putin before his war on Ukraine escalates.
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