linux-kernel - Re: [PATCH 5/6] PCI: acpiphp: look _RMV method a bit deeper in the hierarhcy

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Date:	Tue, 25 Jun 2013 21:31:23 +0300
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	Andy Shevchenko <andy.shevchenko@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Yinghai Lu <yinghai@...nel.org>, john.ronciak@...el.com,
	miles.j.penner@...el.com, bruce.w.allan@...el.com,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-pci@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH 5/6] PCI: acpiphp: look _RMV method a bit deeper in the
 hierarhcy

On Tue, Jun 25, 2013 at 09:15:47PM +0300, Andy Shevchenko wrote:
> On Tue, Jun 25, 2013 at 7:22 PM, Mika Westerberg
> <mika.westerberg@...ux.intel.com> wrote:
> 
> > The acpiphp driver finds out whether the device is hotpluggable by checking
> > whether it has _RMV method behind it (and if it returns 1). However, at
> > least Acer Aspire S5 with Thunderbolt host router has this method placed
> > behind device called EPUP (endpoint upstream port?) and not directly behind
> > the root port as can be seen from the ASL code below:
> 
> []
> 
> 
> > +static acpi_status pcihp_evaluate_rmv(acpi_handle handle, u32 lvl,
> > +                                     void *context, void **return_not_used)
> > +{
> > +       unsigned long long *removable = context;
> > +       unsigned long long value;
> > +       acpi_status status;
> > +
> > +       status = acpi_evaluate_integer(handle, "_RMV", NULL, &value);
> > +       if (ACPI_SUCCESS(status) && value) {
> 
> So, there is a chance the caller gets back uninitialized *context.
> Let's assume that is by design.
> 
> > +               *removable = value;
> > +               return AE_CTRL_TERMINATE;
> > +       }
> > +       return AE_OK;
> > +}
> 
> 
> > +static bool pcihp_is_removable(acpi_handle handle, size_t depth)
> > +{
> > +       unsigned long long removable = 0;
> > +       acpi_status status;
> > +
> > +       status = pcihp_evaluate_rmv(handle, 0, &removable, NULL);
> > +       if ((status == AE_CTRL_TERMINATE) && removable)
> 
> Here you already have removable not equal zero.

Hmm, removable is initialized to zero just few lines above... Did I miss
something obvious?

> Internal braces could be removed, but it's up top you.

I'll remove them in the next revision.

Thanks.
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