linux-kernel - Re: [PATCH v5 2/8] acpi: fix enumeration (visited) flags for bus rescans

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Date:	Thu, 7 Jul 2016 12:00:13 +0300
From:	Mika Westerberg <mika.westerberg@...ux.intel.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Octavian Purdila <octavian.purdila@...el.com>,
	Len Brown <lenb@...nel.org>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	Mark Brown <broonie@...nel.org>,
	Wolfram Sang <wsa@...-dreams.de>,
	Joel Becker <jlbec@...lplan.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	linux-efi@...r.kernel.org, linux-i2c <linux-i2c@...r.kernel.org>,
	linux-spi <linux-spi@...r.kernel.org>,
	lkml <linux-kernel@...r.kernel.org>,
	Irina Tirdea <irina.tirdea@...el.com>,
	Leonard Crestez <leonard.crestez@...el.com>
Subject: Re: [PATCH v5 2/8] acpi: fix enumeration (visited) flags for bus
 rescans

On Wed, Jul 06, 2016 at 11:09:44PM +0200, Rafael J. Wysocki wrote:
> On Wednesday, July 06, 2016 06:37:46 PM Octavian Purdila wrote:
> > On Wed, Jul 6, 2016 at 6:03 PM, Mika Westerberg
> > <mika.westerberg@...ux.intel.com> wrote:
> > > On Fri, Jul 01, 2016 at 11:19:06PM +0300, Octavian Purdila wrote:
> > >> If the ACPI tables changes as a result of a dinamically loaded table and
> > >> a bus rescan is required the enumeration/visited flag are not
> > >> consistent.
> > >>
> > >> I2C/SPI are not directly enumerated in acpi_bus_attach(), however the
> > >> visited flag is set. This makes it impossible to check if an ACPI device
> > >> has already been enumerated by the I2C and SPI subsystems. To fix this
> > >> issue we only set the visited flags if the device is not I2C or SPI.
> > >>
> > >> With this change we also need to remove setting visited to false from
> > >> acpi_bus_attach(), otherwise if we rescan already enumerated I2C/SPI
> > >> devices we try to re-enumerate them.
> > >>
> > >> Note that I2C/SPI devices can be enumerated either via a scan handler
> > >> (when using PRP0001) or via regular device_attach(). In either case
> > >> the flow goes through acpi_default_enumeration() which makes it the
> > >> ideal place to mark the ACPI device as enumerated.
> > >
> > > Hmm, this somehow fails to enumerate PRP0001 devices.
> > >
> > > I'm adding following SSDT to my initrd and the resulting device is never
> > > enumerated on SPI bus (it exists in /sys/bus/acpi/devices). If I use
> > > normal ACPI IDs (non-PRP0001) then it works fine.
> > >
> > 
> > I specifically tested with PRP0001 via initrd with I2C, I am not sure
> > why it does not work on SPI. I'll give it a try tomorrow when I have
> > access to my setup.
> 
> OK, I'll wait for this test to conclude before applying the series, then. :-)

I tested again and it works fine. I probably had an older version of the
series applied or something like that. Now, I'm able to see my AT25 SPI
eeprom successfully probed:

[    7.264705] at25 spi-PRP0001:00: 1 KByte at25 eeprom, pagesize 32

Sorry about the confusion.