Messages in this thread | | | From | Thinh Nguyen <> | Subject | Re: [PATCH] usb: dwc3: Clear DWC3_EVENT_PENDING when count is 0 | Date | Wed, 1 Feb 2023 18:57:46 +0000 |
| |
On Tue, Jan 31, 2023, Linyu Yuan wrote: > hi Thinh, > > > regarding your suggestion, assume it is not PCIe type, still have one > question, > > > - if (evt->flags & DWC3_EVENT_PENDING) > + if (evt->flags & DWC3_EVENT_PENDING) { > + if (!evt->count) { > + u32 reg = dwc3_readl(dwc->regs, DWC3_GEVNTSIZ(0)); > + > + if (!(reg & DWC3_GEVNTSIZ_INTMASK)) > + evt->flags &= ~DWC3_EVENT_PENDING; > > do we need to return IRQ_WAKE_THREAD ?
No, if evt->count is 0, but GEVNTCOUNT is > 0, the controller will generate interrupt. The evt->count will be updated and the events will be handled on the next interrupt.
> > + } > return IRQ_HANDLED; > > as here return IRQ HANDLED, how can we make sure a new IRQ will be handled > after previous IRQ thread clean PENDING flag ?
If evt->count > 0, that means the bottom half is still running. So, leave it be. If evt->count == 0, then the cached events are processed, we're safe to clear the PENDING flag. New interrupt will be generated if GEVNTCOUNT is > 0.
> > + } > > > also for non-PCIe controller, consider IRQ mask register working correctly, > > consider a case IRQ happen before IRQ thread exit, here just return > IRQ_HANDLED. > > once IRQ thread exit, it will clean PENDING flag, so next IRQ event will run > normally. > > if 정재훈 saw PENDING flag is not cleared, does it mean IRQ thread have no > chance to exit ?
The PENDING flag should be cleared eventually when the bottom half completes. I don't expect the interrupt storm to block the IRQ thread forever, but I can't guarantee the device behavor. 정재훈 can confirm. This change should resolve the interrupt storm.
BR, Thinh
| |