linux-kernel - Re: [PATCH 1/2] usb: dwc3: core: Introduce dwc3_device

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Date:	Wed, 16 Mar 2016 15:55:43 +0200
From:	Felipe Balbi <balbi@...nel.org>
To:	Roger Quadros <rogerq@...com>, John Youn <johnyoun@...opsys.com>
Cc:	nsekhar@...com, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, Roger Quadros <rogerq@...com>
Subject: Re: [PATCH 1/2] usb: dwc3: core: Introduce dwc3_device_reinit()


heh, +john

Felipe Balbi <balbi@...nel.org> writes:
> [ text/plain ]
>
> Hi,
>
> Roger Quadros <rogerq@...com> writes:
>> [ text/plain ]
>> We will need this function for a workaround.
>> The function issues a softreset only to the device
>> controller and performs minimal re-initialization
>> so that the device controller can be usable.
>>
>> As some code is similar to dwc3_core_init() take out
>> common code into dwc3_get_gctl_quirks().
>>
>> We add a new member (prtcap_mode) to struct dwc3 to
>> keep track of the current mode in the PRTCAPDIR register.
>>
>> Signed-off-by: Roger Quadros <rogerq@...com>
>
> I must say, I don't like this at all :-p There's ONE known silicon which
> needs this because of a poor silicon integration which took an IP with a
> known erratum where it can't be made to work on lower speeds and STILL
> was integrated without a superspeed PHY.
>
> There's a reason why I never tried to push this upstream myself ;-)
>
> I'm really thinking we might be better off adding a quirk flag to skip
> the metastability workaround and allow this ONE silicon to set the
> controller to lower speed.
>
> John, can you check with your colleagues if we would ever fall into
> STAR#9000525659 if we set maximum speed to high speed during driver
> probe and never touch it again ? I would assume we don't really fall
> into the metastability workaround, right ? We're not doing any sort of
> PM for dwc3...
>
> -- 
> balbi
> [ signature.asc: application/pgp-signature ]

-- 
balbi

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