Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753522AbaGGOQN (ORCPT ); Mon, 7 Jul 2014 10:16:13 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:51100 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753276AbaGGOQK (ORCPT ); Mon, 7 Jul 2014 10:16:10 -0400 Date: Mon, 7 Jul 2014 10:16:09 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Tuomas Tynkkynen cc: Stephen Warren , Thierry Reding , Greg Kroah-Hartman , Felipe Balbi , , , , , Subject: Re: [PATCH v2 3/4] USB: EHCI: tegra: Fix probe order issue leading to broken USB In-Reply-To: <1404436179-10745-4-git-send-email-ttynkkynen@nvidia.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 4 Jul 2014, Tuomas Tynkkynen wrote: > The Tegra USB complex has a particularly annoying misdesign: some of the > UTMI pad configuration registers are global for all the 3 USB controllers > on the chip, but those registers are located in the first controller's > register space and will be cleared when the reset to the first > controller is asserted. Currently, this means that if the 1st controller > were to finish probing after the 2nd or 3rd controller, USB would not > work at all. > > Fix this situation by always resetting the 1st controller before doing > any other setup to any of the controllers, and then never ever reset the > first controller again. As the UTMI registers are related to the PHY, > the PHY driver should probably reset the Tegra controllers instead, > but since old device trees only have reset phandles in the EHCI nodes, > do it here, which means a bit of device tree groveling. Those old DTs > also won't get the reset fix from this commit, so we'll dev_warn() them, > but the driver will still keep probing successfully. > > Signed-off-by: Tuomas Tynkkynen > --- > v2 changes: assume we can find the usb1 reset from the PHY DT node, > don't fail if it's not found but just issue a warning > drivers/usb/host/ehci-tegra.c | 62 +++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 59 insertions(+), 3 deletions(-) Acked-by: Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/