W dniu 1 grudnia 2009 09:59 użytkownik Michel Dänzer
<[email protected]> napisał:
>> Could you tell me how can I wait for vblank from kernel space, please?
>> I see there is drm_wait_vblank but this is not yet exported. I tried
>> export this and use this with _DRM_VBLANK_ABSOLUTE so I hit
>> > DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
>> but that was busy waiting I think, as my desktop was almost not usable.
>>
>> Also Alex believe I should *not* use drm_* for syncing my kernel
>> module code with vblank.
>
> E.g. you could just call drm_vblank_get() before you need vblank
> interrupts to occur, drm_vblank_put() after you don't need them anymore
> and handle the rest from the IRQ handler.

Thanks you! I'll try that today later.

Could you just explain what is drm_wait_vblank for? I expected it to
sleep my process and wake it up interruptible on IRQ. But I'm not sure
that anymore. Also it expected drm_file parameter which AFAIK is never
passed from gpu driver, but from drm to gpu driver.

-- 
Rafał

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