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V4L/DVB (4090): Fix cinergyt2_poll() to allow non-blocking IO on frontend
cinergyt2_poll()" shouldn't return (POLLIN | POLLRDNORM | POLLPRI) when there are no pending events. User space programs that do non-bocking IO using "select()" and/or "poll()" would otherwise produce high system load. Acked-by: Andreas Oberritter <obi@linuxtv.org> Signed-off-by: Axel Dyks <xl@xlsigned.net> Acked-by: Andreas Oberritter <obi@linuxtv.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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@ -544,15 +544,19 @@ static unsigned int cinergyt2_poll (struct file *file, struct poll_table_struct
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{
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struct dvb_device *dvbdev = file->private_data;
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struct cinergyt2 *cinergyt2 = dvbdev->priv;
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unsigned int mask = 0;
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if (cinergyt2->disconnect_pending || mutex_lock_interruptible(&cinergyt2->sem))
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return -ERESTARTSYS;
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poll_wait(file, &cinergyt2->poll_wq, wait);
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if (cinergyt2->pending_fe_events != 0)
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mask |= (POLLIN | POLLRDNORM | POLLPRI);
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mutex_unlock(&cinergyt2->sem);
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return (POLLIN | POLLRDNORM | POLLPRI);
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return mask;
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}
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