From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [PATCH V1 4/4] usb: gadget: tegra-xudc: add port_speed_quirk Date: Tue, 28 Apr 2020 14:25:12 +0200 Message-ID: <20200428122512.GN3592148@ulmo> References: <1587022460-31988-1-git-send-email-nkristam@nvidia.com> <1587022460-31988-5-git-send-email-nkristam@nvidia.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="NJSRbAqOy4NeGDns" Return-path: Content-Disposition: inline In-Reply-To: <1587022460-31988-5-git-send-email-nkristam-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Nagarjuna Kristam Cc: balbi-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org --NJSRbAqOy4NeGDns Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Apr 16, 2020 at 01:04:20PM +0530, Nagarjuna Kristam wrote: > Add port_speed_quirk that modify below registers to limit/restore OTG > port speed to GEN1/GEN2. > SSPX_CORE_CNT56 > SSPX_CORE_CNT57 > SSPX_CORE_CNT65 > SSPX_CORE_CNT66 > SSPX_CORE_CNT67 > SSPX_CORE_CNT72 >=20 > The basic idea is to make SCD intentionally fail, reduce SCD timeout and > force device transit to TSEQ. Enable this flag to only Tegra194. >=20 > Based on work by WayneChang >=20 > Signed-off-by: Nagarjuna Kristam > --- > drivers/usb/gadget/udc/tegra-xudc.c | 106 ++++++++++++++++++++++++++++++= ++++++ > 1 file changed, 106 insertions(+) You're telling readers what you're doing, but after reading the commit message, I have no idea why this is being done. Can you provide more information on why exactly is this needed? Why do we have to limit the OTG port speed? Thierry --NJSRbAqOy4NeGDns Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAl6oIKgACgkQ3SOs138+ s6H1XRAAgIkN+EUOOO1bRRCqdItpBhUzAnXz56qxx16NpYjpIjJPHwPtCDwb2XhK NK6gSk93H07QtoJtWLRt74q5c/exqcYbFDpP1Zx1tnPaK9IlTi0x450TBO6cW5QC NDeOAyRwckbJT16Iab59ZOM6uSIW2VnB2eHHmEiq46mKPm/TQb2aE3lJMjkNskE7 ZzW7SCNwfkJu7r8WcDq/+4jYjg+/0viQ/jd8gyZCJ+WqQu+G6qlPws2D7sVlta6Z PjC4lWFddArpC6W1Xvhq+I0cDJ4ActilTeIeOnSPF60T52S1Uso4cJRBn0AwGcaG Eoab3z2D9s1HkbvCwbteWpMnXWuscXasxKonQ71Z4ifwcQFxoXRtNLBFKrX+Zdxy azEmdmu/6WF5AY28LvmM36UzWvQgPcXimOE2Bb+fOUOb7jW4qtqTNbBPtSJg8zqP NlzMxQ5JDfxhdG7W/A9MzV31cuDjLSWCI59BGSEOcoKjN3ehapybAHxfacvpqarz VoEvo/KG2AykqH8Xx5DJU7eLyOHZKSTF86mHKCucU2G+7NcdMi+j8kQwhzY41rDH 2G4Jh8ycg/HpjIdQLXebWLZh+afh2M0LxX9ShM6MJ4KrTph0hbnzf72mCHhmRzFk C5g1JrwbmRR+tdwsfbSUHOnK7S4J+kG65VCCuyKexREetPWzeY0= =KTH2 -----END PGP SIGNATURE----- --NJSRbAqOy4NeGDns--