From 08d3874636a20b8852f8eea1c6ad1054234c9ae6 Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Wed, 21 Jun 2017 03:44:55 +0200 Subject: [PATCH] drm/radeon: Allow vblank_disable_immediate. MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit With instantaneous high precision vblank timestamping that updates at leading edge of vblank, a cooked hw vblank counter which increments at leading edge of vblank, and reliable page flip execution and completion at leading edge of vblank, we should meet the requirements for fast/immediate vblank irq disable/enable. Testing on Linux-4.12-rc5 + drm-next on a Radeon HD 5770 (DCE 4) with timing measurement equipment indicates this works fine, so allow immediate vblank disable for power saving. For debugging in case of unexpected trouble, booting with kernel cmdline option drm.vblankoffdelay=0 (or echo 0 > /sys/module/drm/parameters/vblankoffdelay) would keep vblank irqs permanently on to approximate old behavior. Reviewed-and-Tested-by: Michel Dänzer Signed-off-by: Mario Kleiner Cc: Alex Deucher Cc: Michel Dänzer Signed-off-by: Alex Deucher --- drivers/gpu/drm/radeon/radeon_irq_kms.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c index 7aacb44df201..186076492f64 100644 --- a/drivers/gpu/drm/radeon/radeon_irq_kms.c +++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c @@ -283,6 +283,10 @@ int radeon_irq_kms_init(struct radeon_device *rdev) int r = 0; spin_lock_init(&rdev->irq.lock); + + /* Disable vblank irqs aggressively for power-saving */ + rdev->ddev->vblank_disable_immediate = true; + r = drm_vblank_init(rdev->ddev, rdev->num_crtc); if (r) { return r; -- 2.30.2