On Wed, Jan 30, 2019 at 10:16:34AM +0100, Felix Fietkau wrote: > On 2019-01-30 09:37, Stanislaw Gruszka wrote: > > On Tue, Jan 29, 2019 at 01:40:57PM +0100, Lorenzo Bianconi wrote: > >> > Felix Fietkau <nbd@xxxxxxxx> writes: > >> > > >> > > On 2019-01-29 13:07, Kalle Valo wrote: > >> > >> Felix Fietkau <nbd@xxxxxxxx> writes: > >> > >> > >> > >>> On 2019-01-29 12:47, Kalle Valo wrote: > >> > >>>> Stanislaw Gruszka <sgruszka@xxxxxxxxxx> writes: > >> > >>>> > >> > >>>>> We can configure beaconing, but without TBTT interrupt we > >> > >>>>> can not support PS buffering. This can be added later using > >> > >>>>> kernel hrtimer, if we can keep it in sycn with device timer. > >> > >>>>> > >> > >>>>> I tested AP and IBSS modes. > >> > >>>> > >> > >>>> So how does this work reliably so that there's no packet loss with > >> > >>>> clients using power save? > >> > >>> > >> > >>> There will be multicast packet loss for clients using power save. > >> > >> > >> > >> Isn't that a problem? At least as a normal user I would very frustrated > >> > >> if sometimes my connection work and sometimes not, for example if I'm > >> > >> trying discover devices from my network. Hopefully nobody won't use USB > >> > >> devices for any real AP stuff, but still enabling something which we > >> > >> know doesn't work realiably is concerning. > >> > > > >> > > I agree. Maybe we should leave out the flag for AP mode in this patch > >> > > until we have PS buffering and leave the rest of the code intact. > >> > > >> > At least for me that sounds good. > >> > >> We can support ps buffering in AP as well using a hrtimer. In this way we > >> can reuse most of the existing code > > > > Yes, but there is issue to address, since kernel timer and device TBT > > timer are independed, they possibly can get out of sync after some time, > > for example few hours or days. So there is need to prevent/fix this > > somehow. > We could read the TSF timer value from the hardware and sync the hrtimer > against that. Ok then. I'll implement hrtimer solution and repost this set. Patch 6 will no longer be necessery. Regards Stanislaw
