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Date:   Thu, 26 Sep 2019 11:09:36 +0300
From:   "Shevchenko, Andriy" <andriy.shevchenko@intel.com>
To:     "Schmauss, Erik" <erik.schmauss@intel.com>
Cc:     "Moore, Robert" <robert.moore@intel.com>,
        Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Ferry Toth <fntoth@gmail.com>, Len Brown <lenb@kernel.org>,
        Jacek Anaszewski <jacek.anaszewski@gmail.com>,
        Pavel Machek <pavel@ucw.cz>, Dan Murphy <dmurphy@ti.com>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "devel@acpica.org" <devel@acpica.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "nv@vosn.de" <nv@vosn.de>
Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
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On Wed, Sep 25, 2019 at 09:13:34PM +0300, Schmauss, Erik wrote:
> > -----Original Message-----
> > From: Ferry Toth <ftoth@telfort.nl>
> > Sent: Thursday, September 12, 2019 12:37 PM
> > To: Moore, Robert <robert.moore@intel.com>; Nikolaus Voss
> > <nikolaus.voss@loewensteinmedical.de>; Shevchenko, Andriy
> > <andriy.shevchenko@intel.com>; Schmauss, Erik <erik.schmauss@intel.com>;
> > Rafael J. Wysocki <rjw@rjwysocki.net>
> > Cc: Len Brown <lenb@kernel.org>; Jacek Anaszewski
> > <jacek.anaszewski@gmail.com>; Pavel Machek <pavel@ucw.cz>; Dan Murphy
> > <dmurphy@ti.com>; linux-acpi@vger.kernel.org; devel@acpica.org; linux-
> > kernel@vger.kernel.org; nv@vosn.de
> > Subject: Re: [PATCH] ACPICA: make acpi_load_table() return table index
> > 
> > Op 12-09-19 om 16:19 schreef Moore, Robert:
> > > Nikolaus,
> > > The ability to unload an ACPI table (especially AML tables such as SSDTs) is in
> > the process of being deprecated in ACPICA -- since it is also deprecated in the
> > current ACPI specification. This is being done because of the difficulty of
> > deleting the namespace entries for the table.  FYI, Windows does not properly
> > support this function either.
> > 
> > I really hope this is not the case. On x86 loading/unloading SSDTs has proven to
> > be a powerful way to handle reconfigurable hardware without rebooting and
> > without requiring dedicated platform drivers. Same for user plugable hardware
> > on i2c/spi busses.
> > 
> > This has worked before and will violate the "don't break user space" rule.
> 
> If the table index wasn't being used, how did this work before?
> Which commit broke this?
> 
> Bob and I are trying to understand if this is a regression or a new feature request...

It is a regression as I explained in my bisecting message.

Before it uses acpi_tb_* API directly.
I thought Bob already got the idea.

-- 
With Best Regards,
Andy Shevchenko