Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752367AbaBTU1x (ORCPT ); Thu, 20 Feb 2014 15:27:53 -0500 Received: from mga09.intel.com ([134.134.136.24]:61319 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750705AbaBTU1w (ORCPT ); Thu, 20 Feb 2014 15:27:52 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,514,1389772800"; d="scan'208";a="486795515" Message-ID: <53066544.8030404@intel.com> Date: Thu, 20 Feb 2014 21:27:48 +0100 From: "Rafael J. Wysocki" Organization: Intel Technology Poland Sp. z o. o., KRS 101882, ul. Slowackiego 173, 80-298 Gdansk User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Jiang Liu CC: David Airlie , Dave Airlie , Emil Velikov , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] nouveau, ACPI: fix regression caused by b072e53 References: <1392888200-27567-1-git-send-email-jiang.liu@linux.intel.com> In-Reply-To: <1392888200-27567-1-git-send-email-jiang.liu@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/20/2014 10:23 AM, Jiang Liu wrote: > Fix regression caused by commit b072e53, which breaks loading nouveau > driver on optimus laptops. > > On some platforms, ACPI _DSM method (nouveau_op_dsm_muid, function 0) > has special requirements on the fourth parameter, which is different > from ACPI specifications. So revert to the private implementation > to check availability of _DSM functions instead of using common > acpi_check_dsm() interface. > > Reported-and-Tested-by: Maarten Lankhorst > Signed-off-by: Jiang Liu I'm taking this, because the commit that introduced the regression went in through my tree. In the future I'll appreciate CCing ACPI-related patches to linux-acpi, however. Thanks, Rafael > --- > drivers/gpu/drm/nouveau/nouveau_acpi.c | 26 ++++++++++++++++++++++++-- > 1 file changed, 24 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c > index 4ef83df..83face3 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_acpi.c > +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c > @@ -106,6 +106,29 @@ static int nouveau_optimus_dsm(acpi_handle handle, int func, int arg, uint32_t * > return 0; > } > > +/* > + * On some platforms, _DSM(nouveau_op_dsm_muid, func0) has special > + * requirements on the fourth parameter, so a private implementation > + * instead of using acpi_check_dsm(). > + */ > +static int nouveau_check_optimus_dsm(acpi_handle handle) > +{ > + int result; > + > + /* > + * Function 0 returns a Buffer containing available functions. > + * The args parameter is ignored for function 0, so just put 0 in it > + */ > + if (nouveau_optimus_dsm(handle, 0, 0, &result)) > + return 0; > + > + /* > + * ACPI Spec v4 9.14.1: if bit 0 is zero, no function is supported. > + * If the n-th bit is enabled, function n is supported > + */ > + return result & 1 && result & (1 << NOUVEAU_DSM_OPTIMUS_CAPS); > +} > + > static int nouveau_dsm(acpi_handle handle, int func, int arg) > { > int ret = 0; > @@ -207,8 +230,7 @@ static int nouveau_dsm_pci_probe(struct pci_dev *pdev) > 1 << NOUVEAU_DSM_POWER)) > retval |= NOUVEAU_DSM_HAS_MUX; > > - if (acpi_check_dsm(dhandle, nouveau_op_dsm_muid, 0x00000100, > - 1 << NOUVEAU_DSM_OPTIMUS_CAPS)) > + if (nouveau_check_optimus_dsm(dhandle)) > retval |= NOUVEAU_DSM_HAS_OPT; > > if (retval & NOUVEAU_DSM_HAS_OPT) { -- 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/