On Tue, Nov 24, 2015 at 7:21 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > On Sun, Nov 22, 2015 at 02:05:16PM +0000, Simon Arlott wrote: >> There is a level triggered interrupt for the watchdog timer as part of >> the bcm63xx_timer device. The interrupt occurs when the hardware watchdog >> timer reaches 50% of the remaining time. >> >> It is not possible to mask the interrupt within the bcm63xx_timer device. >> To get around this limitation, handle the interrupt by restarting the >> watchdog with the current remaining time (which will be half the previous >> timeout) so that the interrupt occurs again at 1/4th, 1/8th, etc. of the >> original timeout value until the watchdog forces a reboot. >> >> The software timer was restarting the hardware watchdog with a 85 second >> timeout until the software timer expired, and then causing a panic() >> about 42.5 seconds later when the hardware interrupt occurred. The >> hardware watchdog would not reboot until a further 42.5 seconds had >> passed. >> >> Remove the software timer and rely on the hardware timer directly, >> reducing the maximum timeout from 256 seconds to 85 seconds >> (2^32 / WDT_HZ). >> > > Florian, > > can you have a look into this patch and confirm that there is no better > way to clear the interrupt status ? While the watchdog interrupt can't be masked, it should be able to be cleared by writing 1 to the appropriate bit in the timer block's interrupt status register. At least the broadcom sources do so. Jonas
