Re: [PATCH] ACPI / scan: set status to 0 if _STA failed

["Rafael J. Wysocki" <rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org>]

On Thursday, November 19, 2015 12:11:49 PM Mika Westerberg wrote:
> On Thu, Nov 19, 2015 at 11:05:25AM +0800, Aaron Lu wrote:
> > Some ACPI node's _STA will touch operation region field, since the
> > evaluation of _STA in acpi_bus_type_and_status is very early, the
> > operation region handler is not ready yet. Instead of fail that function
> > and not creating the acpi_device node consequently, set status to 0 so
> > that later when the driver for that device is probing, it can find
> > the acpi_device node and proceed normally. And at that time, the
> > handler for the operation region is ready and its _STA evaluation will
> > succeed, its present status can be checked there.
> > 
> > Even there will be no driver using this node later, it doesn't seem
> > hurt to have one more acpi_device node created with status set to 0.
> > 
> > This happens on Microsoft Surface 3, where the SPI device node NTRG's
> > _STA touches GPIO fields and the SPI core driver will only enumerate SPI
> > devices from ACPI if the acpi_device node is 1: created; 2: _STA
> > indicates it's present.
> > 
> > Note that due to another problem in SPI driver, for NTRG to be actually
> > enumerated, some changes have to be made in the SPI layer, which is
> > addressed by Mika(not send out yet):
> > https://bugzilla.kernel.org/show_bug.cgi?id=104291#c23
> > 
> > Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=104291
> > Reported-by: Bastien Nocera <bugzilla-0MeiytkfxGOsTnJN9+BGXg@public.gmane.org>
> > Signed-off-by: Aaron Lu <aaron.lu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> 
> I don't know any better solution to this,
> 
> Reviewed-by: Mika Westerberg <mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>

Applied, thanks!

Rafael

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