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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: "Hans de Goede" <hdegoede@redhat.com>,
	"Daniel Vetter" <daniel.vetter@intel.com>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
	"Jarkko Nikula" <jarkko.nikula@linux.intel.com>,
	"Wolfram Sang" <wsa@the-dreams.de>, "Len Brown" <lenb@kernel.org>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>,
	dri-devel@lists.freedesktop.org,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Takashi Iwai <tiwai@suse.de>,
	"russianneuromancer @ ya . ru" <russianneuromancer@ya.ru>,
	linux-i2c@vger.kernel.org
Subject: Re: [PATCH 3/7] i2c: designware-baytrail: Take punit lock on bus acquire
Date: Sun, 08 Jan 2017 17:27:19 +0200	[thread overview]
Message-ID: <1483889239.26691.16.camel@linux.intel.com> (raw)
In-Reply-To: <20170108134427.8392-4-hdegoede@redhat.com>

On Sun, 2017-01-08 at 14:44 +0100, Hans de Goede wrote:
> Take the punit lock to stop others from accessing the punit while the
> pmic i2c bus is in use. This is necessary because accessing the punit
> from the kernel may result in the punit trying to access the pmic i2c
> bus, which results in a hang when it happens while we own the pmic i2c
> bus semaphore.
> 
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=155241
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> Tested-by: tagorereddy <tagore.chandan@gmail.com>
> ---
>  drivers/i2c/busses/i2c-designware-baytrail.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-designware-baytrail.c
> b/drivers/i2c/busses/i2c-designware-baytrail.c
> index 3effc9a..cf7a2a0 100644
> --- a/drivers/i2c/busses/i2c-designware-baytrail.c
> +++ b/drivers/i2c/busses/i2c-designware-baytrail.c
> 

> @@ -62,6 +62,8 @@ static void reset_semaphore(struct dw_i2c_dev *dev)

> +	iosf_mbi_punit_unlock();

> @@ -79,6 +81,8 @@ static int baytrail_i2c_acquire(struct dw_i2c_dev
> +	iosf_mbi_punit_lock();

For me it looks a bit asymmetrical.

Can we use acquire()/release()?

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

  reply	other threads:[~2017-01-08 15:27 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-08 13:44 [PATCH 0/7] coordinate cht i2c-pmic and i915-punit accesses Hans de Goede
2017-01-08 13:44 ` [PATCH 1/7] x86/platform/intel/iosf_mbi: Add a mutex for punit access Hans de Goede
2017-01-08 15:16   ` Andy Shevchenko
2017-01-08 15:30     ` Hans de Goede
2017-01-08 15:35       ` Andy Shevchenko
2017-01-08 13:44 ` [PATCH 2/7] x86/platform/intel/iosf_mbi: Add a pmic bus access notifier Hans de Goede
2017-01-08 15:21   ` Andy Shevchenko
2017-01-08 13:44 ` [PATCH 3/7] i2c: designware-baytrail: Take punit lock on bus acquire Hans de Goede
2017-01-08 15:27   ` Andy Shevchenko [this message]
2017-01-08 15:39     ` Hans de Goede
2017-01-12 18:45   ` Wolfram Sang
2017-01-15 11:21     ` Hans de Goede
2017-01-15 11:45       ` Wolfram Sang
2017-01-15 15:11         ` Hans de Goede
2017-01-15 15:17           ` Wolfram Sang
2017-01-08 13:44 ` [PATCH 4/7] i2c: designware-baytrail: Call pmic_bus_access_notifier_chain Hans de Goede
2017-01-08 15:23   ` Andy Shevchenko
2017-01-12 18:45   ` Wolfram Sang
2017-01-08 13:44 ` [PATCH 5/7] drm/i915: Add intel_uncore_suspend / resume functions Hans de Goede
2017-01-08 13:44 ` [PATCH 6/7] drm/i915: Listen for pmic bus access notifications Hans de Goede
2017-01-08 13:44 ` [PATCH 7/7] drm/i915: Take punit lock when modifying punit settings Hans de Goede
2017-01-08 15:34   ` Andy Shevchenko
2017-01-08 15:42     ` Hans de Goede

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