From: Mika Westerberg <mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Jarkko Nikula
<jarkko.nikula-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] spi: Check conflicting CS based on spi->chip_select instead of device name
Date: Thu, 9 Jan 2014 16:27:29 +0200 [thread overview]
Message-ID: <20140109142729.GA2494@intel.com> (raw)
In-Reply-To: <20140109140646.GT31886-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
On Thu, Jan 09, 2014 at 02:06:46PM +0000, Mark Brown wrote:
> On Thu, Jan 09, 2014 at 03:23:55PM +0200, Mika Westerberg wrote:
>
> > In case of a buggy BIOS that lists multiple SPI devices sharing the same
> > chip select (even though they should use different) the current code fails
> > to detect that and allows the devices to be added to the bus.
>
> This actually also points out another issue - if we have two instances
> of a device on different buses they could end up with the same
> dev_name() if they have the same chip select. Hrm.
I don't think that can happen, at least in case of ACPI, since each ACPI
device has unique name, such as 'INT33C0:00' - the ':00' suffix is the
"instance" number ACPI core gives for devices.
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WARNING: multiple messages have this Message-ID (diff)
From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org,
Jarkko Nikula <jarkko.nikula@linux.intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] spi: Check conflicting CS based on spi->chip_select instead of device name
Date: Thu, 9 Jan 2014 16:27:29 +0200 [thread overview]
Message-ID: <20140109142729.GA2494@intel.com> (raw)
In-Reply-To: <20140109140646.GT31886@sirena.org.uk>
On Thu, Jan 09, 2014 at 02:06:46PM +0000, Mark Brown wrote:
> On Thu, Jan 09, 2014 at 03:23:55PM +0200, Mika Westerberg wrote:
>
> > In case of a buggy BIOS that lists multiple SPI devices sharing the same
> > chip select (even though they should use different) the current code fails
> > to detect that and allows the devices to be added to the bus.
>
> This actually also points out another issue - if we have two instances
> of a device on different buses they could end up with the same
> dev_name() if they have the same chip select. Hrm.
I don't think that can happen, at least in case of ACPI, since each ACPI
device has unique name, such as 'INT33C0:00' - the ':00' suffix is the
"instance" number ACPI core gives for devices.
next prev parent reply other threads:[~2014-01-09 14:27 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-09 13:23 [PATCH] spi: Check conflicting CS based on spi->chip_select instead of device name Mika Westerberg
2014-01-09 13:23 ` Mika Westerberg
[not found] ` <1389273835-8615-1-git-send-email-mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2014-01-09 13:59 ` Jarkko Nikula
2014-01-09 13:59 ` Jarkko Nikula
[not found] ` <52CEAB4A.605-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2014-01-09 16:05 ` Mika Westerberg
2014-01-09 16:05 ` Mika Westerberg
2014-01-09 14:06 ` Mark Brown
2014-01-09 14:06 ` Mark Brown
[not found] ` <20140109140646.GT31886-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2014-01-09 14:27 ` Mika Westerberg [this message]
2014-01-09 14:27 ` Mika Westerberg
[not found] ` <20140109142729.GA2494-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2014-01-09 14:36 ` Mark Brown
2014-01-09 14:36 ` Mark Brown
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