On Wed, Jun 21, 2017 at 3:22 AM, Michel Dänzer <michel at daenzer.net> wrote:
> On 21/06/17 10:44 AM, Mario Kleiner wrote:
>> 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 <mario.kleiner.de at gmail.com>
>> Cc: Alex Deucher <alexander.deucher at amd.com>
>> Cc: Michel Dänzer <michel.daenzer at amd.com>
>> ---
>> 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;
>>
>
> Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>
Applied patches 2 and 3.
Thanks,
Alex
>
>
> --
> Earthling Michel Dänzer | http://www.amd.com
> Libre software enthusiast | Mesa and X developer
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