On Thu, Feb 29, 2024 at 08:45:54AM +0000, Sean Young wrote: > On Tue, Feb 27, 2024 at 05:59:40PM +0100, Stefan Wahren wrote: > > Hi Chris, > > > > Am 27.02.24 um 16:32 schrieb Chris Morgan: > > > I have a series of devices with GPIO controlled force feedback that > > > this driver helps us control better. So I'm looking forward to this, > > > thank you. > > Thanks for testing. I didn't had much time recently and i was fighting > > with hr timer resolution stuff. But will try to send the next version in > > March. > > > Note that when I set the resolution too low (I got confused and set > > > the period to 255) my device locked up hard and only a forced > > > power cycle could bring it back. > > Unfortunately this is a general design issue by driving the GPIO by a > > kernel driver and "expected" behavior. I didn't have a good solution for > > it yet. > > When we reprogram the timer with hrtimer_forward(), we could check whether > we have overrun - i.e. we are already beyond the expires time. This could > be a hint that a) we cannot generate the pwm signal and b) this might > be what causes the hang, because we are returning HRTIMER_RESTART yet > no new expires has been programmed. I mean something like: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/media/rc/pwm-ir-tx.c#n144 Sean
