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From: Lars-Peter Clausen <lars@metafoo.de>
To: Jonathan Cameron <jic23@kernel.org>
Cc: "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>
Subject: Bottom half trigger function never called when using the sysfs trigger
Date: Fri, 15 Jun 2012 15:08:29 +0200	[thread overview]
Message-ID: <4FDB33CD.2090805@metafoo.de> (raw)

hi,

The sysfs trigger uses iio_trigger_poll_chained which calls
handle_nested_irq. The problem now is that for nested IRQs the primary
handler is not called. Which obviously breaks drivers which have a bottom
half trigger function.

This behaviour was introduced in commit 1f785681 ("staging:iio:trigger sysfs
userspace trigger rework."). The commit message says you are "awaiting
comments on using the nested_irq_trick", but not why it is necessary to use
nested IRQs. And honestly I don't get why it would be necessary either.
handle_nested_irq is supposed to be used with chained IRQs if we are already
running in a thread handler of parent. Neither seems to be true here.

- Lars

             reply	other threads:[~2012-06-15 13:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-15 13:08 Lars-Peter Clausen [this message]
2012-06-15 13:32 ` Bottom half trigger function never called when using the sysfs trigger Jonathan Cameron
2012-06-15 14:57   ` Lars-Peter Clausen
2012-06-15 14:59     ` Jonathan Cameron

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