On Thu, 2 Aug 2018, Michael Schmitz wrote:
This redundant load of the ICR has been in the driver code for a long
time. There's a small chance it is intentional,
Actually, it is intentional.
so at least minimal testing might be in order.
Minimal testing is almost useless if you are trying to prove the absence
of race conditions. SCSI arbitration is a race between targets by design;
so a race between the CPU and the 5380 is going to be hard to observe.
Finn - does the ICR_ARBITRATION_LOST bit have to be cleared by a write
to the mode register?
Something like that: the write to the mode register does clear the
ICR_ARBITRATION_LOST bit, because it clears the MR_ARBITRATE bit.
In that case, the first load would have been redundant and can be
omitted without changing driver behaviour?
This code is a faithful rendition of the arbitration flow chart in the
datasheet, so even if you are right, I wouldn't want to change the code.