Hi, On Mon, Jan 10, 2022 at 09:28:55AM -0800, Guenter Roeck wrote: > While playing with SMBus alert functionality, I noticed the following > messages if alert was active on more than once device. > > smbus_alert 3-000c: SMBALERT# from dev 0x0c, flag 0 > smbus_alert 3-000c: no driver alert()! > > or: > > smbus_alert 3-000c: SMBALERT# from dev 0x28, flag 0 > > This is seen if multiple devices assert alert at the same time and at least > one of them does not or not correctly implement SMBus arbitration. > > Once it starts, this message repeats forever at high rate. > Worst case, the problem turn resulted in system crashes after a while. > > The following two patches fix the problem for me. The first patch > aborts the endless loop in smbus_alert() if no handler is found > for an alert address. The second patch sends alerts to all devices > with alert handler if that situation is observed. > > I split the changes into two patches since I figured that the first patch > might be easier to accept. However, both patches are really needed to > fix the problem for good. > > Note that there is one situation which is not addressed by this set of > patches: If the corrupted address points to yet another device with alert > handler on the same bus, the alert handler of that device will be called. > If it is not a source of the alert, we are back to the original problem. > I do not know how to address this case. > > ---------------------------------------------------------------- > Guenter Roeck (2): > i2c: smbus: Improve handling of stuck alerts > i2c: smbus: Send alert notifications to all devices if source not found > > drivers/i2c/i2c-smbus.c | 64 ++++++++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 58 insertions(+), 6 deletions(-) Looking through the patches I carry locally, I just noticed that I never got a reply to this series. Is there a problem with it, or did it just get lost ? Thanks, Guenter
