> -----Original Message----- > From: Dmitry Torokhov [mailto:dmitry.torokhov@xxxxxxxxx] > Sent: Monday, February 5, 2018 4:46 PM > To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx> > Cc: andriy.shevchenko@xxxxxxxxxxxxxxx; jdelvare@xxxxxxx; > alex.hung@xxxxxxxxxxxxx; rjw@xxxxxxxxxxxxx; lenb@xxxxxxxxxx; > gregkh@xxxxxxxxxxxxxxxxxxx; davem@xxxxxxxxxxxxx; > mika.westerberg@xxxxxxxxxxxxxxx; f.fainelli@xxxxxxxxx; kishon@xxxxxx; > karniksayli1995@xxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 2/2] ACPI / osi: add DMI quirk for Dell systems > > On Mon, Feb 05, 2018 at 05:36:18PM +0000, Mario.Limonciello@xxxxxxxx wrote: > > > -----Original Message----- > > > From: Andy Shevchenko [mailto:andriy.shevchenko@xxxxxxxxxxxxxxx] > > > Sent: Monday, February 5, 2018 8:15 AM > > > To: Jean Delvare <jdelvare@xxxxxxx>; Alex Hung <alex.hung@xxxxxxxxxxxxx> > > > Cc: rjw@xxxxxxxxxxxxx; lenb@xxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; > > > davem@xxxxxxxxxxxxx; mika.westerberg@xxxxxxxxxxxxxxx; > f.fainelli@xxxxxxxxx; > > > dmitry.torokhov@xxxxxxxxx; kishon@xxxxxx; karniksayli1995@xxxxxxxxx; > linux- > > > acpi@xxxxxxxxxxxxxxx; Limonciello, Mario <Mario_Limonciello@xxxxxxxx> > > > 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? > Neither Nouveau nor the NVIDIA blob have support for RTD3. Last I heard it's waiting on NVIDIA releasing something Nouveau needs. So.. Eventually? For now it's better to not hang though. That's part of why we wanted to enable this via a transient OSI string, to let this be removed by Linux whenever the driver does grow support. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
