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Commit 774dd5d9 authored by Axel Dyks's avatar Axel Dyks Committed by Mauro Carvalho Chehab
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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: default avatarAndreas Oberritter <obi@linuxtv.org>

Signed-off-by: default avatarAxel Dyks <xl@xlsigned.net>
Acked-by: default avatarAndreas Oberritter <obi@linuxtv.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent be4f4519

drivers/media/dvb/cinergyT2/cinergyT2.c

+5 −1
Original line number Original line Diff line number Diff line
@@ -544,15 +544,19 @@ static unsigned int cinergyt2_poll (struct file *file, struct poll_table_struct 
{

{

	struct dvb_device *dvbdev = file->private_data;

	struct dvb_device *dvbdev = file->private_data;

	struct cinergyt2 *cinergyt2 = dvbdev->priv;

	struct cinergyt2 *cinergyt2 = dvbdev->priv;

       unsigned int mask = 0;





	if (cinergyt2->disconnect_pending || mutex_lock_interruptible(&cinergyt2->sem))

	if (cinergyt2->disconnect_pending || mutex_lock_interruptible(&cinergyt2->sem))

		return -ERESTARTSYS;

		return -ERESTARTSYS;





	poll_wait(file, &cinergyt2->poll_wq, wait);

	poll_wait(file, &cinergyt2->poll_wq, wait);





       if (cinergyt2->pending_fe_events != 0)

	       mask |= (POLLIN | POLLRDNORM | POLLPRI);



	mutex_unlock(&cinergyt2->sem);

	mutex_unlock(&cinergyt2->sem);





	return (POLLIN | POLLRDNORM | POLLPRI);

       return mask;

}

}