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Commit 71c6efd9 authored by Orczykowski, Juergen's avatar Orczykowski, Juergen Committed by Linus Torvalds
Browse files

intelfb: fix ring space calculation 



If there is less than RING_MIN_FREE available in the ring buffer,
dinfo->ring_space is set to a big value forcing wait_ring to return.

Fix by making ring space = 0 if ring space < RING_MIN_FREE.

Signed-off-by: default avatarDave Airlie <airlied@gmail.com>
Signed-off-by: default avatarAntonino Daplas <adaplas@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 33a9f640

drivers/video/intelfb/intelfbhw.c

+21 −13
Original line number Diff line number Diff line
@@ -1428,6 +1428,24 @@ static void refresh_ring(struct intelfb_info *dinfo); 
static void reset_state(struct intelfb_info *dinfo);

static void do_flush(struct intelfb_info *dinfo);



static  u32 get_ring_space(struct intelfb_info *dinfo)

{

	u32 ring_space;



	if (dinfo->ring_tail >= dinfo->ring_head)

		ring_space = dinfo->ring.size -

			(dinfo->ring_tail - dinfo->ring_head);

	else

		ring_space = dinfo->ring_head - dinfo->ring_tail;



	if (ring_space > RING_MIN_FREE)

		ring_space -= RING_MIN_FREE;

	else

		ring_space = 0;



	return ring_space;

}



static int

wait_ring(struct intelfb_info *dinfo, int n)

{
@@ -1442,13 +1460,8 @@ wait_ring(struct intelfb_info *dinfo, int n) 
	end = jiffies + (HZ * 3);

	while (dinfo->ring_space < n) {

		dinfo->ring_head = INREG(PRI_RING_HEAD) & RING_HEAD_MASK;

		if (dinfo->ring_tail + RING_MIN_FREE < dinfo->ring_head)

			dinfo->ring_space = dinfo->ring_head

				- (dinfo->ring_tail + RING_MIN_FREE);

		else

			dinfo->ring_space = (dinfo->ring.size +

					     dinfo->ring_head)

				- (dinfo->ring_tail + RING_MIN_FREE);

		dinfo->ring_space = get_ring_space(dinfo);



		if (dinfo->ring_head != last_head) {

			end = jiffies + (HZ * 3);

			last_head = dinfo->ring_head;
@@ -1513,12 +1526,7 @@ refresh_ring(struct intelfb_info *dinfo) 


	dinfo->ring_head = INREG(PRI_RING_HEAD) & RING_HEAD_MASK;

	dinfo->ring_tail = INREG(PRI_RING_TAIL) & RING_TAIL_MASK;

	if (dinfo->ring_tail + RING_MIN_FREE < dinfo->ring_head)

		dinfo->ring_space = dinfo->ring_head

			- (dinfo->ring_tail + RING_MIN_FREE);

	else

		dinfo->ring_space = (dinfo->ring.size + dinfo->ring_head)

			- (dinfo->ring_tail + RING_MIN_FREE);

	dinfo->ring_space = get_ring_space(dinfo);

}



static void