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Message-ID: <1554890928.21725.6.camel@suse.com>
Subject: Re: lan78xx: About 8000 usb interrupts per second when idle
From:   Oliver Neukum <oneukum@suse.com>
To:     Jisheng Zhang <Jisheng.Zhang@synaptics.com>,
        Minas Harutyunyan <minas.harutyunyan@synopsys.com>
Cc:     Douglas Anderson <dianders@chromium.org>,
        Stefan Wahren <stefan.wahren@i2se.com>,
        "linux-rpi-kernel@lists.infradead.org" 
        <linux-rpi-kernel@lists.infradead.org>,
        Woojung Huh <woojung.huh@microchip.com>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Date:   Wed, 10 Apr 2019 12:08:48 +0200
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On Mi, 2019-04-10 at 09:37 +0000, Jisheng Zhang wrote:
> On Tue, 9 Apr 2019 09:28:16 +0000 Minas Harutyunyan wrote:

Hi,

> > dwc2 in host mode enable SOF interrupts if any periodic EP are in use.
> > So, 8000 interrupts per second is expectant behavior.
> 
> Makes sense. 8 microframes each 1ms, so 8*1000 = 8000 interrupts/s

The remedy for that would be using autosuspend. That just tells us that
support for autosuspend is not optional.

	Regards
		Oliver