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 R9 380 Tonga Pro (DCE 10) 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. Signed-off-by: Mario Kleiner <[email protected]> Cc: Alex Deucher <[email protected]> Cc: Michel Dänzer <[email protected]> --- drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c index 62da6c5..a28f8aa 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c @@ -220,6 +220,10 @@ int amdgpu_irq_init(struct amdgpu_device *adev) int r = 0; spin_lock_init(&adev->irq.lock); + + /* Disable vblank irqs aggressively for power-saving */ + adev->ddev->vblank_disable_immediate = true; + r = drm_vblank_init(adev->ddev, adev->mode_info.num_crtc); if (r) { return r; -- 2.7.4 _______________________________________________ Nouveau mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/nouveau
