From: Peter Chen <peter.chen@nxp.com>
To: Felipe Balbi <balbi@kernel.org>,
"mathias.nyman@intel.com" <mathias.nyman@intel.com>
Cc: "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
dl-linux-imx <linux-imx@nxp.com>,
"pawell@cadence.com" <pawell@cadence.com>,
"rogerq@ti.com" <rogerq@ti.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
Jun Li <jun.li@nxp.com>
Subject: RE: [PATCH 1/8] usb: cdns3: add runtime PM support
Date: Mon, 31 Aug 2020 10:59:51 +0000 [thread overview]
Message-ID: <AM7PR04MB71572A2B1EDC6D379B1CBDA88B510@AM7PR04MB7157.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <87sgc39ls8.fsf@kernel.org>
>
> Peter Chen <peter.chen@nxp.com> writes:
> > Introduce runtime PM and wakeup interrupt handler for cdns3, the
> > runtime PM is default off since other cdns3 has not implemented glue
> > layer support for runtime PM.
>
> it should be left disabled by default even after every glue implements it.
> Enabling runtime PM is a policy decision better left to userspace, IMO.
>
> > When the controller is in low power mode, the lpm flag will be set.
> > The interrupt triggered later than lpm flag is set considers as wakeup
> > interrupt and handled at cdns_drd_irq. Once the wakeup
>
> This sentence doesn't parse very well. Do you want to rephrase it?
>
> > occurs, it first disables interrupt to avoid later interrupt
> > occurrence since the controller is in low power mode at that time, and
> > access registers may be invalid at that time. At wakeup handler, it
> > will call pm_runtime_get to wakeup controller, and at runtime resume
> > handler, it will enable interrupt again.
>
> Then what? Are you going to, somehow, process pending interrupts? At what
> point?
>
> > The API platform_suspend is introduced for glue layer to implement
> > platform specific PM sequence.
>
> I really think that's unnecessary. Why can't we rely on parent->child
> relationship for this?
>
Hi Felipe,
This is the old version patch; I replied your questions at your reply for new
version at last Friday, thanks.
Peter
next prev parent reply other threads:[~2020-08-31 10:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 10:32 [PATCH 0/8] usb: cdns3: add runtime PM support Peter Chen
2020-05-22 10:32 ` [PATCH 1/8] " Peter Chen
2020-08-31 10:01 ` Felipe Balbi
2020-08-31 10:59 ` Peter Chen [this message]
2020-08-31 11:27 ` Felipe Balbi
2020-05-22 10:32 ` [PATCH 2/8] usb: cdns3: imx: add glue layer runtime pm implementation Peter Chen
2020-08-31 10:04 ` Felipe Balbi
2020-05-22 10:32 ` [PATCH 3/8] usb: host: xhci-plat: add platform data support Peter Chen
2020-05-22 10:32 ` [PATCH 4/8] usb: host: xhci-plat: add .suspend_quirk for struct xhci_plat_priv Peter Chen
2020-08-31 10:06 ` Felipe Balbi
2020-08-31 11:00 ` Peter Chen
2020-05-22 10:32 ` [PATCH 5/8] usb: host: xhci-plat: delete the unnecessary code Peter Chen
2020-05-22 10:32 ` [PATCH 6/8] usb: host: xhci-plat: add priv flag for skip_phy_initialization Peter Chen
2020-05-22 10:32 ` [PATCH 7/8] usb: cdns3: host: add .suspend_quirk for xhci-plat.c Peter Chen
2020-05-22 10:32 ` [PATCH 8/8] usb: cdns3: host: add xhci_plat_priv's flag skip_phy_initialization Peter Chen
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