On Wednesday, December 18, 2013 11:21 AM, Stephen Warren wrote: > On 12/16/2013 11:46 PM, Jingoo Han wrote: > > Use devm_request_irq() to make cleanup paths simpler. > > This may not be safe. The interrupt used by the I2C controllers on the > BCM2835 chip is shared between two controllers. In theory, you could run > into a condition where you're remove()ing the driver for one of the > controller (a), while the driver for controller (b) is still active, yet > the HW for controller (a) comes along and triggers an interrupt after > remove() but before the devm IRQ cleanup. That would result in the IRQ > handler for controller (a) executing after the remove() of the > associated device, which could cause a variety of problems. Hi Stephen, I appreciate you detailed and kind description. :-) If there is possible side effect, the patch should not be merged. Wolfram Sang, Please ignore this patch. Thank you. Best regards, Jingoo Han > You might be able to make this safe by explicitly clearing any IRQ > enable registers in remove(), but leaving the code using plain > request_irq() might be simpler. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
