From: Felipe Balbi <balbi@kernel.org>
To: John Youn <John.Youn@synopsys.com>, Roger Quadros <rogerq@ti.com>,
        John Youn <John.Youn@synopsys.com>
Cc: nsekhar@ti.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] usb: dwc3: core: Introduce dwc3_device_reinit()
In-Reply-To: <56EC5452.8030509@synopsys.com>
References: <1458133551-3071-1-git-send-email-rogerq@ti.com> <1458133551-3071-2-git-send-email-rogerq@ti.com> <87r3fah8h3.fsf@intel.com> <87lh5ih6hs.fsf@intel.com> <56EC5452.8030509@synopsys.com>
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Date: Mon, 21 Mar 2016 09:14:48 +0200
Message-ID: <87r3f4z4if.fsf@intel.com>
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Hi,

John Youn <John.Youn@synopsys.com> writes:
> [ text/plain ]
> On 3/16/2016 6:56 AM, Felipe Balbi wrote:
>>=20
>> heh, +john
>>=20
>> Felipe Balbi <balbi@kernel.org> writes:
>>> [ text/plain ]
>>>
>>> Hi,
>>>
>>> Roger Quadros <rogerq@ti.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@ti.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...
>>>
>
> Hi Felipe,
>
> I don't know much about this but I will check with the engineers and
> get back to you.

Thank you John ;-)

=2D-=20
balbi

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