On Fri, May 20, 2022 at 12:33:24PM +0200, Wolfram Sang wrote: > A customer experienced a race condition with 'repeated starts' when a > System Management Interrupt took over for 30us and more. The problem was > that during the SMI a new MAT interrupt came in because we set up the > 'repeated start' condition. But the old one was not acknowledged yet. > So, when it was acknowledged after the SMI, the new MAT interrupt was > lost, confusing the state machine of the driver. > > The fix consists of two parts. First, we do not clear the status > register for 'repeated starts' when preparing the next message anymore. > The interrupt handlers for sending and receiving data is now solely > responsible for that and it makes the code easier to follow, in fact. > Secondly, clearing the status register is now split up to handle MAT > interrupts independently. This avoids the race condition because the old > MAT interrupt will be now cleared before we initiate the "repeated > start" condition. > > Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> > Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx> Applied to for-next, thanks!
Attachment:
signature.asc
Description: PGP signature
