From: Antti Palosaari <crope@iki.fi>
To: Olli Salonen <olli.salonen@iki.fi>,
Peter Zijlstra <peterz@infradead.org>
Cc: Nibble Max <nibble.max@gmail.com>,
linux-media <linux-media@vger.kernel.org>,
Mauro Carvalho Chehab <mchehab@s-opensource.com>,
wsa@the-dreams.de
Subject: Re: Regression: DVBSky S960 USB tuner doesn't work in 4.10 or newer
Date: Wed, 18 Apr 2018 11:49:57 +0300 [thread overview]
Message-ID: <18b9e776-3558-30ed-f616-a0ba8e4d177d@iki.fi> (raw)
In-Reply-To: <CAAZRmGw9DTHX65cYch6ozjGejMnDNQx_aNF-RYPRo+E4COEoRA@mail.gmail.com>
On 04/18/2018 07:49 AM, Olli Salonen wrote:
> Thank you for your response Peter!
>
> Indeed, it seems strange. dvbsky.c driver seems to use mutex_lock in
> very much the same way as many other drivers. I've now confirmed that
> I can get a 4.10 kernel with working DVBSky S960 by reverting the
> following 4 patches:
>
> 549bdd3 Revert "locking/mutex: Add lock handoff to avoid starvation"
> 3210f31 Revert "locking/mutex: Restructure wait loop"
> 418a170 Revert "locking/mutex: Simplify some ww_mutex code in
> __mutex_lock_common()"
> 0b1fb8f Revert "locking/mutex: Enable optimistic spinning of woken waiter"
> c470abd Linux 4.10
These kind of issues tend to be timing issues very often. Just add some
sleeps to i2c adapter algo / usb control messages and test.
regards
Antti
--
http://palosaari.fi/
next prev parent reply other threads:[~2018-04-18 8:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-04 11:41 Regression: DVBSky S960 USB tuner doesn't work in 4.10 or newer Olli Salonen
2018-04-08 17:44 ` Olli Salonen
2018-04-09 9:14 ` Peter Zijlstra
2018-04-18 4:49 ` Olli Salonen
2018-04-18 8:49 ` Antti Palosaari [this message]
2018-04-27 14:25 ` Olli Salonen
2018-04-27 16:33 ` Mauro Carvalho Chehab
2018-04-28 6:01 ` Olli Salonen
2018-05-10 11:04 ` Mauro Carvalho Chehab
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