Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753000AbaKCPuo (ORCPT ); Mon, 3 Nov 2014 10:50:44 -0500 Received: from bear.ext.ti.com ([192.94.94.41]:41540 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751816AbaKCPul (ORCPT ); Mon, 3 Nov 2014 10:50:41 -0500 Date: Mon, 3 Nov 2014 09:50:11 -0600 From: Felipe Balbi To: Mika Westerberg CC: Felipe Balbi , David Cohen , Linus Walleij , "linux-kernel@vger.kernel.org" , "linux-gpio@vger.kernel.org" , stable , Subject: Re: [PATCH] pinctrl: baytrail: show output gpio state correctly on Intel Baytrail Message-ID: <20141103155011.GH27425@saruman> Reply-To: References: <20141028144249.GD8123@saruman> <20141031132005.GB1273@saruman> <20141031162339.GA7136@psi-dev26.jf.intel.com> <20141031184509.GA2224@psi-dev26.jf.intel.com> <20141103092402.GA1304@lahna.fi.intel.com> <20141103150048.GB27425@saruman> <20141103152743.GB1618@lahna.fi.intel.com> <20141103154207.GC1618@lahna.fi.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="tT3UgwmDxwvOMqfu" Content-Disposition: inline In-Reply-To: <20141103154207.GC1618@lahna.fi.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --tT3UgwmDxwvOMqfu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Mon, Nov 03, 2014 at 05:42:07PM +0200, Mika Westerberg wrote: > On Mon, Nov 03, 2014 at 05:27:43PM +0200, Mika Westerberg wrote: > > On Mon, Nov 03, 2014 at 09:00:48AM -0600, Felipe Balbi wrote: > > > On Mon, Nov 03, 2014 at 11:24:02AM +0200, Mika Westerberg wrote: > > > > On Fri, Oct 31, 2014 at 11:45:09AM -0700, David Cohen wrote: > > > > > > I think adding the module exit + allowing this driver to be a m= odule > > > > > > would be a good approach. Then we don't need to force generic x= 86 kernel > > > > > > binaries to always have this driver. Unless Mathias or Mika kno= ws a > > > > > > constraint to force this driver to be builtin only. > > > > >=20 > > > > > It helps if I CC them when asking for feedback :) > > > > >=20 > > > > > Mathias, Mika, do you know any constraint that forces pinctrl-bay= trail > > > > > to be bool? > > > >=20 > > > > The only constraint that has been keeping this driver as bool is th= at > > > > some machines like, Asus T100, uses ACPI GPIO operation regions for > > > > toggling GPIOs to get things like sensor hub powered on. The GPIO > > > > operation region code does not yet handle -EPROBE_DEFER so only way= to > > > > ensure that the operation region is there is to have the driver com= piled > > > > in to the kernel. > > >=20 > > > But that's not enough excuse to have every single x86 in the market > > > shipping with this driver. Think about a distro kernel, most likely t= his > > > gets enabled and it's wrong in 80% of the cases. > >=20 > > True, but see below. > >=20 > > > It would be nicer to add EPROBE_DEFER support, convert this into > > > tristate and have default =3D M if BAYTRAIL, or something. > >=20 > > If it were simple as that we would have done that already. Please check > > drivers/gpio/gpiolib-acpi.c:acpi_gpio_adr_space_handler() and tell me > > how we can do that. >=20 > Actually the above is not the problem because we already have registered > the GPIO chip and hence we have the GPIO available to the firmware code. what happens before you registered the gpio chip ? It takes some time =66rom head.S to gpiochip_irqchip_add(). Anywhere between that time, firmware could try to access gpios and the same problem would occur. > The real problem is that if the ACPI GPIO operation handler is not there > at the time firmware decides to do something it will just skip things > that depend on the operation region. So if it has a GPIO that is used to > turn on sensor hub or touch panel or whatever, this will not be done and > it results that the device in question might not work properly. that's an issue that needs solving, but forcing every x86 kernel to ship with this driver, is not a proper solution. --=20 balbi --tT3UgwmDxwvOMqfu Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUV6QzAAoJEIaOsuA1yqRE66QP/1rC0KgtEScVJCq8+I14sHEN jyw6vwxXPsFpMmhJPKDoaVk6ZGkYmLgY4Xkq3R5yfy/pmg2NPh4FZzYfX58xpuT4 HdeLE8aejAsf2DZ83vp0mHwyBVh7xBXjkiZCj+jBrPpFwlGG9WktovZjZ+E91vzA qD5MWVdK8cHMwS570O8WcDebEhco84KWqZpcAi+lh277ldkXdDgrWmPQgKxiw1G/ H+WUJyUNBrZnCJQp2oKDuzD2deOnxx5aPIrQih3zRQ+7Zwozp5mHuN1bdGV4+KtN 3eLB4KjGC3aVqmSGoNIiHCaXD+EBMvrDKWR7Q2XzP+ex8RCK9InEU0WVvL9lpmPV TN54ILhPPSxpr4o3l/tXQdbIq1fxi2Y+CYElAT3umjWqROmg1M/qMVlkjAt76GaK pyqAWKXs6GoILYCxiY89dqZhegMAdpAPxJHDwSDsmrTKMpFHHyqyROFxDT1g9i/b ez0LcNTR5pTtcnm1JSY2gbY+iTsaROxouFVzXlq/vWd8SqYO1AwEyHMgwg7W2AS1 zLG9mbpR3I/r2Y7uTkEHScJJE/YmL8uYozmAyH6HN21eUgk4TIhWHnVTHGy4nqcZ QZgxHtooO7J6/FOrNTlfsOuhvblW83cT5+1RIDgkQmDPApKOP6Ux7/EGY6RkJuiB +EIS/BKkvSt8IUr1nQfy =l3w5 -----END PGP SIGNATURE----- --tT3UgwmDxwvOMqfu-- -- 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/