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?
--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy
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