From: Russell King <rmk+kernel@arm.linux.org.uk>
Date: Sun, 22 Jan 2012 20:58:55 +0000 (+0000)
Subject: MFD: ucb1x00-ts: fix resume failure
X-Git-Tag: v3.3-rc2~18^2~1^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0af5e4c36e70cfd4ae96d3704a425c414f530f2a;p=pandora-kernel.git

MFD: ucb1x00-ts: fix resume failure

If the ucb1x00 touchscreen is resumed while the touchscreen is being
touched, the main thread stops responding.  This occurs because two
things happen:

1. When we suspended, we were woken up, and executed the loop.
   Finding that the touchscreen was not pressed, we prepare to
   schedule for a maximum timeout, before being stopped in
   try_to_freeze().

2. an irq occurs, we disable the irq, and mark it as disabled,
   and wake the thread.  This wake occurs while the thread is
   still within __refrigerator()

3. The thread is unfrozen, and __refrigerator() sets the threads
   state back to INTERRUPTIBLE.

We then drop into schedule_timeout() with an infinite timeout and the
IRQ disabled.  This prevents any further screen touches activating
the thread.

Fix this by using kthread_freezable_should_stop() which handles the
freezing issues for us outside of the hotspot where the task state
matters.  Include a flag to ignore the touchscreen until it is
released to avoid sending unintended data to the application.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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