If the CSB head/tail pointers are unchanged, we can skip the update of the CSB register afterwards.
Signed-off-by: Chris Wilson <[email protected]> Reviewed-by: Joonas Lahtinen <[email protected]> --- drivers/gpu/drm/i915/intel_lrc.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index 7db9c49450f9..a46a05f0e79c 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -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), -- 2.11.0 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
