On Mon, Jul 27, 2020 at 08:13:46PM +0200, Wolfram Sang wrote: > > > Can you confirm that even if we have irq pending at the i2c IP core > > level, as long as we execute Step 2. below (to disable/mask all slave > > interrupts), after 'enable_irq' is called, we still will not receive any > > further i2c slave interrupt? > > This is HW dependant. From my tests with Renesas HW, this is not the > case. But the actual error case was impossible to trigger for me, so > far. I might try again later. But even in the worst case, I would only > get a "spurious interrupt" and not an NULL-ptr OOPS. Let me explain how I verified this: 0) add a debug print whenever the slave irq part is called 1) Put a 2 second delay after disable_irq() and before clearing interrupt enable register 2) unbind the slave driver in the background, triggering the 2s delay 3) during the delay, try to read from the to-be-unbound slave in the foreground 4) ensure there is no prinout from the slave irq Worked fine for me with the Renesas R-Car I2C IP interface. As mentioned before, I couldn't trigger a bad case with my setup. So, I hope this new fix will work for Rayagonda's test case, too!
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