From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH 2/2] ACPI / osi: add DMI quirk for Dell systems Date: Mon, 5 Feb 2018 14:45:31 -0800 Message-ID: <20180205224531.GA46524@dtor-ws> References: <1517388005-14852-1-git-send-email-alex.hung@canonical.com> <1517388005-14852-2-git-send-email-alex.hung@canonical.com> <20180205141447.6e1442ac@endymion> <1517840100.22495.25.camel@linux.intel.com> <5de252ed95ee48eab3bd8deeea5c610a@ausx13mpc120.AMER.DELL.COM> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pl0-f67.google.com ([209.85.160.67]:40804 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751671AbeBEWpf (ORCPT ); Mon, 5 Feb 2018 17:45:35 -0500 Received: by mail-pl0-f67.google.com with SMTP id g18so12771817plo.7 for ; Mon, 05 Feb 2018 14:45:35 -0800 (PST) Content-Disposition: inline In-Reply-To: <5de252ed95ee48eab3bd8deeea5c610a@ausx13mpc120.AMER.DELL.COM> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Mario.Limonciello@dell.com Cc: andriy.shevchenko@linux.intel.com, jdelvare@suse.de, alex.hung@canonical.com, rjw@rjwysocki.net, lenb@kernel.org, gregkh@linuxfoundation.org, davem@davemloft.net, mika.westerberg@linux.intel.com, f.fainelli@gmail.com, kishon@ti.com, karniksayli1995@gmail.com, linux-acpi@vger.kernel.org On Mon, Feb 05, 2018 at 05:36:18PM +0000, Mario.Limonciello@dell.com wrote: > > -----Original Message----- > > From: Andy Shevchenko [mailto:andriy.shevchenko@linux.intel.com] > > Sent: Monday, February 5, 2018 8:15 AM > > To: Jean Delvare ; Alex Hung > > Cc: rjw@rjwysocki.net; lenb@kernel.org; gregkh@linuxfoundation.org; > > davem@davemloft.net; mika.westerberg@linux.intel.com; f.fainelli@gmail.com; > > dmitry.torokhov@gmail.com; kishon@ti.com; karniksayli1995@gmail.com; linux- > > acpi@vger.kernel.org; Limonciello, Mario > > Subject: Re: [PATCH 2/2] ACPI / osi: add DMI quirk for Dell systems > > > > On Mon, 2018-02-05 at 14:14 +0100, Jean Delvare wrote: > > > > > On Wed, 31 Jan 2018 00:40:05 -0800, Alex Hung wrote: > > > > A number of Dell systems require an OEM _OSI string "Linux-Dell- > > > > Video" as > > > > a BIOS workaround for a system hang bug caused by discrete VGA. The > > > > form of > > > > the OEM _OSI string is discussed in Documentation/acpi/osi.txt and > > > > is > > > > defined by each OEM. > > > > > > I admit I don't understand how it is the operating system's job to > > > carry the information from the BIOS to the BIOS. > > > > > > + for (i = 0; i < OSI_STRING_ENTRIES_MAX; i++) { > > > > + osi = &osi_setup_entries[i]; > > > > + if (!strcmp(osi->string, str)) { > > > > > > This can only happen if the user passes acpi_osi=Linux-Dell-Video or > > > acpi_osi=!Linux-Dell-Video on the boot command line, right? > > > > > > > + osi->enable = true; > > > > > > Does this not prevent the user from explicitly disabling it with > > > acpi_osi=!Linux-Dell-Video ? > > > > Playing with OSI string is a bad idea. I wouldn't do anything while > > Rafael, or even Len can confirm that is the right thing to do. > > > > For me, AFAIK we need to be bug-to-bug compatible with Windows (at least > > on ACPICA side), so, what Windows exactly does on such laptops? > > > > The issue that's being worked around isn't an ACPICA interpreter issue, but it's > a graphics device configuration issue. > > Windows expects to use RTD3 on the NVIDIA GPU but Linux drivers > don't. It leads to system hangs on the Linux side. Can we adjust Linux drivers to do the right thing? Or is it regarding the binary NVIDIA blob? Thanks. -- Dmitry