Re: [PATCH] usb: dwc3: Clear DWC3_EVENT_PENDING when count is 0

From: Linyu Yuan <quic_linyyuan@quicinc.com>
To: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Cc: 정재훈 <jh0801.jung@samsung.com>,
	"'Felipe Balbi'" <balbi@kernel.org>,
	"'Greg Kroah-Hartman'" <gregkh@linuxfoundation.org>,
	"'open list:USB XHCI DRIVER'" <linux-usb@vger.kernel.org>,
	"'open list'" <linux-kernel@vger.kernel.org>,
	"'Seungchull Suh'" <sc.suh@samsung.com>,
	"'Daehwan Jung'" <dh10.jung@samsung.com>
Subject: Re: [PATCH] usb: dwc3: Clear DWC3_EVENT_PENDING when count is 0
Date: Tue, 31 Jan 2023 14:38:55 +0800	[thread overview]
Message-ID: <c76d426c-c65b-1334-627a-1a6c615ddd93@quicinc.com> (raw)
In-Reply-To: <20230111022720.mcrhdrthgwlwszcv@synopsys.com>

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  ?

+               }
                 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 ?

+       }

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 ?