On Wed, Jul 29, 2020 at 07:24:57PM -0700, Badhri Jagan Sridharan wrote: > "tReceiverResponse 15 ms Section 6.6.2 > The receiver of a Message requiring a response Shall respond > within tReceiverResponse in order to ensure that the > sender’s SenderResponseTimer does not expire." > > When the cpu complex is busy running other lower priority > work items, TCPM's work queue sometimes does not get scheduled > on time to meet the above requirement from the spec. > Moving to kthread_work apis to run with real time priority. > Just lower than the default threaded irq priority, > MAX_USER_RT_PRIO/2 + 1. (Higher number implies lower priority). > > Further, as observed in 1ff688209e2e, moving to hrtimers to > overcome scheduling latency while scheduling the delayed work. > > TCPM has three work streams: > 1. tcpm_state_machine > 2. vdm_state_machine > 3. event_work > > tcpm_state_machine and vdm_state_machine both schedule work in > future i.e. delayed. Hence each of them have a corresponding > hrtimer, tcpm_state_machine_timer & vdm_state_machine_timer. > > When work is queued right away kthread_queue_work is used. > Else, the relevant timer is programmed and made to queue > the kthread_work upon timer expiry. > > kthread_create_worker only creates one kthread worker thread, > hence single threadedness of workqueue is retained. > > Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx> > Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> > Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> > --- > Changes since v1:(Guenter's suggestions) > - Remove redundant call to hrtimer_cancel while calling > hrtimer_start. > > Changes since v2:(Greg KH's suggestions) > - Rebase usb-next TOT. > 633198cd2945b7 (HEAD -> usb-next-1) usb: typec: tcpm: Migrate workqueue to RT priority for processing events > fa56dd9152ef95 (origin/usb-next) Merge tag 'usb-serial-5.9-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-next > 25252919a1050e xhci: dbgtty: Make some functions static > b0e02550346e67 xhci: dbc: Make function xhci_dbc_ring_alloc() static > ca6377900974c3 Revert "usb: dwc2: override PHY input signals with usb role switch support" > 09df709cb5aeb2 Revert "usb: dwc2: don't use ID/Vbus detection if usb-role-switch on STM32MP15 SoCs" > 17a82716587e9d USB: iowarrior: fix up report size handling for some devices > e98ba8cc3f8a89 Merge tag 'usb-for-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-next > c97793089b11f7 Merge 5.8-rc7 into usb-next > 92ed301919932f (tag: v5.8-rc7, origin/usb-linus, origin/main) Linux 5.8-rc7 > Hm, still does not apply. I think it has something to do with other patches that landed before yours, can you rebase again? thanks, greg k-h
