Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit a37951ac authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Skip the execlists CSB scan and rewrite if the ring is untouched 



If the CSB head/tail pointers are unchanged, we can skip the update of
the CSB register afterwards.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170124110009.28947-5-chris@chris-wilson.co.uk
parent f747026c

drivers/gpu/drm/i915/intel_lrc.c

+5 −2
Original line number Diff line number Diff line
@@ -574,9 +574,12 @@ static void intel_lrc_irq_handler(unsigned long data) 
		csb = readl(csb_mmio);

		head = GEN8_CSB_READ_PTR(csb);

		tail = GEN8_CSB_WRITE_PTR(csb);

		if (head == tail)

			break;



		if (tail < head)

			tail += GEN8_CSB_ENTRIES;

		while (head < tail) {

		do {

			unsigned int idx = ++head % GEN8_CSB_ENTRIES;

			unsigned int status = readl(buf + 2 * idx);
@@ -601,7 +604,7 @@ static void intel_lrc_irq_handler(unsigned long data) 


			GEM_BUG_ON(port[0].count == 0 &&

				   !(status & GEN8_CTX_STATUS_ACTIVE_IDLE));

		}

		} while (head < tail);



		writel(_MASKED_FIELD(GEN8_CSB_READ_PTR_MASK,

				     GEN8_CSB_WRITE_PTR(csb) << 8),