From: Jarkko Nikula <jarkko.nikula@linux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Hans de Goede <hdegoede@redhat.com>,
Wolfram Sang <wsa@the-dreams.de>, Len Brown <lenb@kernel.org>
Cc: "Mika Westerberg" <mika.westerberg@linux.intel.com>,
"Jani Nikula" <jani.nikula@linux.intel.com>,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
"Takashi Iwai" <tiwai@suse.de>,
"russianneuromancer @ ya . ru" <russianneuromancer@ya.ru>,
linux-i2c@vger.kernel.org,
intel-gfx <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH v5 5/6] i2c: designware-baytrail: Fix race when resetting the semaphore
Date: Tue, 10 Jan 2017 15:16:22 +0200 [thread overview]
Message-ID: <d07aa4d4-77b5-89c8-948c-046d5d9763f2@linux.intel.com> (raw)
In-Reply-To: <1483351617.9552.192.camel@linux.intel.com>
On 01/02/2017 12:06 PM, Andy Shevchenko wrote:
> On Mon, 2017-01-02 at 10:55 +0100, Hans de Goede wrote:
>> Hi,
>>
>> On 02-01-17 10:36, Andy Shevchenko wrote:
>>> On Sun, 2017-01-01 at 21:15 +0100, Hans de Goede wrote:
>>>> Use iosf_mbi_modify instead of iosf_mbi_read + iosf_mbi_write so
>>>> that
>>>> we keep the iosf_mbi_lock locked during the read-modify-write done
>>>> to
>>>> reset the semaphore.
>>>>
>>>
>>> While patch itself looks good to me, I think it reduces a
>>> probability to
>>> race and doesn't eliminate an issue completely.
>>
>> All accesses through this register are done through the
>> iosf_mbi_ helpers, and the modify helper holds the
>> iosf_mbi_lock during the entire read-modify-wrtie cycle,
>> so I don't see how there can still be any issue left.
>
> Ah, seems you are right.
>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
next prev parent reply other threads:[~2017-01-10 13:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-01 20:15 [PATCH v5 1/6] i2c: designware: Rename accessor_flags to flags Hans de Goede
2017-01-01 20:15 ` [PATCH v5 2/6] i2c: designware-baytrail: Pass dw_i2c_dev into helper functions Hans de Goede
2017-01-01 20:15 ` [PATCH v5 3/6] i2c: designware-baytrail: Only check iosf_mbi_available() for shared hosts Hans de Goede
2017-01-01 20:15 ` [PATCH v5 4/6] i2c: designware-baytrail: Disallow the CPU to enter C6 or C7 while holding the punit semaphore Hans de Goede
2017-01-01 20:15 ` [PATCH v5 5/6] i2c: designware-baytrail: Fix race when resetting the semaphore Hans de Goede
2017-01-02 9:36 ` Andy Shevchenko
2017-01-02 9:55 ` Hans de Goede
2017-01-02 10:06 ` Andy Shevchenko
2017-01-10 13:16 ` Jarkko Nikula [this message]
2017-01-01 20:15 ` [PATCH v5 6/6] i2c: designware-baytrail: Add support for cherrytrail Hans de Goede
2017-01-15 15:18 ` [PATCH v5 1/6] i2c: designware: Rename accessor_flags to flags Wolfram Sang
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