From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 9 May 2019 16:23:32 +0200 From: Thierry Reding Subject: Re: [PATCH V2 16/28] PCI: tegra: Set target speed as Gen1 before starting LTSSM Message-ID: <20190509142332.GM8907@ulmo> References: <20190423092825.759-1-mmaddireddy@nvidia.com> <20190423092825.759-17-mmaddireddy@nvidia.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="+ARLBH93C7pgvpZY" Content-Disposition: inline In-Reply-To: <20190423092825.759-17-mmaddireddy@nvidia.com> To: Manikanta Maddireddy Cc: bhelgaas@google.com, robh+dt@kernel.org, mark.rutland@arm.com, jonathanh@nvidia.com, lorenzo.pieralisi@arm.com, vidyas@nvidia.com, linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org List-ID: --+ARLBH93C7pgvpZY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Apr 23, 2019 at 02:58:13PM +0530, Manikanta Maddireddy wrote: > PCIe link up fails with few legacy endpoints if root port advertises both > Gen-1 and Gen-2 speeds in Tegra. This is because link number negotiation > fails if both Gen1 & Gen2 are advertised. Tegra doesn't retry link up by > advertising only Gen1. Hence, the strategy followed here is to initially > advertise only Gen-1 and after link is up, retrain link to Gen-2 speed. >=20 > Tegra doesn't support HW autonomous speed change. Link comes up in Gen1 > even if Gen2 is advertised, so there is no downside of this change. >=20 > This behavior is observed with following two PCIe devices on Tegra, > - Fusion HDTV 5 Express card > - IOGear SIL - PCIE - SATA card >=20 > Signed-off-by: Manikanta Maddireddy > --- > V2: Updated commit log to reflect why this issue is observed on Tegra with > these particular cards >=20 > drivers/pci/controller/pci-tegra.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) Acked-by: Thierry Reding --+ARLBH93C7pgvpZY Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAlzUN+MACgkQ3SOs138+ s6GQrRAAo+2k8UeW7UF1AajkUxrBvVxbQQRIy+pZSYqFbg6dy6nOnB4ZEDVsnEZS gfxZhX8qStod8gWagEMF25nctyiVHuQGU+P07GJY3FIcOEx4Y/EYv0wW65H6OACD gbscLMB5kXRLbVg26nY3SIjB2IZDG/nFXmfdkkDpsOurd4CPulleUAovtp6q1Sfe BAcbDC4vQ5cov/Ms2oJeEtZMBJICGPCDyFLZRU0D+xhuDyEVvFVnmGWM5vPKGAzM hfMXyU4uWkm6TYExw9LMUoFiH5n7NPC4FnbQSO+vLw/9JGtnBu/wXVMAn63IwqcF ezOMxxOeQwGxxbr/aJCF7VGeCNdcxlJvyAlOwESK5nIiAvXHW5mlOAUpuLplIxsS 2cXr75echyXlZlIP4l52qZj8K31E17Y61MWaO0/dwXMw6nEyB9uirZ2pZeSHVFxo apAO6EJoBjWLbIEzKr8DAaZYWdpzu+IArVwFm1+sbasQ7GDM9ail0Q77gXdg2jP7 GXRgT7qwctB93JPqrDfwM/0i7KkKXs2zkV19ga3/2Ae9F+SoaGCElYSOKsuUKQ+t yEg+JROfGJik40qUz/Skr/QR2VB4IMBDEGalKdsq22krZuqCaIx+Py4RgQ69L7+G pJYDV3BBPNdq6RQBP5uC1jyivg75l4kzUOxGMJBhgD2FFyVw0lQ= =BWzF -----END PGP SIGNATURE----- --+ARLBH93C7pgvpZY--