From: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com> To: Stefan Wahren <stefan.wahren@i2se.com>, Minas Harutyunyan <Minas.Harutyunyan@synopsys.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>, Doug Anderson <dianders@chromium.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: Re: [PATCH RFC] usb: dwc2: power off during shutdown Date: Thu, 6 Sep 2018 06:33:07 +0000 [thread overview] Message-ID: <410670D7E743164D87FA6160E7907A56013A7646E0@am04wembxa.internal.synopsys.com> (raw) In-Reply-To: 470783016.30183.1536172949193@email.1und1.de Hi Stefan, On 9/5/2018 10:42 PM, Stefan Wahren wrote: > Hi Minas, > >> Minas Harutyunyan <Minas.Harutyunyan@synopsys.com> hat am 5. September 2018 um 10:37 geschrieben: >> >> >> Hi Stefan, >> >> On 9/1/2018 1:55 PM, Stefan Wahren wrote: >>> Currently USB consumes a lot of power after shutting down a Raspberry Pi 3 >>> (example setup with Ethernet and a keyboard connected). So power off >>> USB on shutdown. >>> >>> Measured on Raspberry Pi 3B with 4.19rc1/multi_v7_defconfig (HDMI, Ethernet >>> and a keyboard connected) >>> >>> Before patch: 2.450 W >>> After patch: 2.090 W >>> >> >> Could you please elaborate. Power measurements done after shutdown? > > I did the following: > > sudo halt > wait until "System halted" appears on the screen > "measured" the current value displayed on my PSU > > You are right that not the same as poweroff. But in even in poweroff the board consumes 0.6 W, but in this case USB is powered down. > >> Why >> your setup continue consume power after shutdown? > > The BCM2835 SoC has a GPU and a ARM core. Linux is running only on the ARM core. The GPU is usually running a close source firmware, which is started at first during boot und runs all the time. > >> Maybe its >> sleep/hibernation mode? > > There isn't much implementation of power management for BCM2835 yet. So i wanted to start with USB. > Even for sleep/hibernation the consumption is much too high. Because the system consumes in idle 1.6 W. > >> >> dwc2 core in your platform which type of power optimization supports: >> partial power down, hibernation or extended hibernation? Please provide >> me GHWCFG4 register value of your core. > > AFAIK all RPis use the same USB IP core: > > GHWCFG4 = 0x1ff00020 Ok, your core doesn't support any power optimization mode. > > Stefan > 1. Could you please explain what is real/physical cause of power saving after your patch: VBUS off, PHY clock stop or any other? 2. Can USB detect remote wake-up signaling from connected keyboard/ethernet before and after your patch? Thanks, Minas
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From: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com> To: Stefan Wahren <stefan.wahren@i2se.com>, Minas Harutyunyan <Minas.Harutyunyan@synopsys.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>, Doug Anderson <dianders@chromium.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: [RFC] usb: dwc2: power off during shutdown Date: Thu, 6 Sep 2018 06:33:07 +0000 [thread overview] Message-ID: <410670D7E743164D87FA6160E7907A56013A7646E0@am04wembxa.internal.synopsys.com> (raw) Hi Stefan, On 9/5/2018 10:42 PM, Stefan Wahren wrote: > Hi Minas, > >> Minas Harutyunyan <Minas.Harutyunyan@synopsys.com> hat am 5. September 2018 um 10:37 geschrieben: >> >> >> Hi Stefan, >> >> On 9/1/2018 1:55 PM, Stefan Wahren wrote: >>> Currently USB consumes a lot of power after shutting down a Raspberry Pi 3 >>> (example setup with Ethernet and a keyboard connected). So power off >>> USB on shutdown. >>> >>> Measured on Raspberry Pi 3B with 4.19rc1/multi_v7_defconfig (HDMI, Ethernet >>> and a keyboard connected) >>> >>> Before patch: 2.450 W >>> After patch: 2.090 W >>> >> >> Could you please elaborate. Power measurements done after shutdown? > > I did the following: > > sudo halt > wait until "System halted" appears on the screen > "measured" the current value displayed on my PSU > > You are right that not the same as poweroff. But in even in poweroff the board consumes 0.6 W, but in this case USB is powered down. > >> Why >> your setup continue consume power after shutdown? > > The BCM2835 SoC has a GPU and a ARM core. Linux is running only on the ARM core. The GPU is usually running a close source firmware, which is started at first during boot und runs all the time. > >> Maybe its >> sleep/hibernation mode? > > There isn't much implementation of power management for BCM2835 yet. So i wanted to start with USB. > Even for sleep/hibernation the consumption is much too high. Because the system consumes in idle 1.6 W. > >> >> dwc2 core in your platform which type of power optimization supports: >> partial power down, hibernation or extended hibernation? Please provide >> me GHWCFG4 register value of your core. > > AFAIK all RPis use the same USB IP core: > > GHWCFG4 = 0x1ff00020 Ok, your core doesn't support any power optimization mode. > > Stefan > 1. Could you please explain what is real/physical cause of power saving after your patch: VBUS off, PHY clock stop or any other? 2. Can USB detect remote wake-up signaling from connected keyboard/ethernet before and after your patch? Thanks, Minas
next prev parent reply other threads:[~2018-09-06 6:33 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-09-01 9:54 [PATCH RFC] usb: dwc2: power off during shutdown Stefan Wahren 2018-09-01 9:54 ` [RFC] " Stefan Wahren 2018-09-05 8:37 ` [PATCH RFC] " Minas Harutyunyan 2018-09-05 8:37 ` [RFC] " Minas Harutyunyan 2018-09-05 18:42 ` [PATCH RFC] " Stefan Wahren 2018-09-05 18:42 ` [RFC] " Stefan Wahren 2018-09-06 6:33 ` Minas Harutyunyan [this message] 2018-09-06 6:33 ` Minas Harutyunyan
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