[PATCH] drm/vkms: Don't warn hrtimer_forward_now failure.

[Tetsuo Handa]

On 2020/05/26 13:18, Tetsuo Handa wrote:
> due to mode->crtc_clock <= 0. Thus, somehow initializing mode->crtc_clock > 0 might be able
> to solve this problem.

Well, I came to think that vkms_enable_vblank() should return an error to the caller
when drm_calc_timestamping_constants() failed...

static int vkms_enable_vblank(struct drm_crtc *crtc)
{
	struct drm_device *dev = crtc->dev;
	unsigned int pipe = drm_crtc_index(crtc);
	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);

	drm_calc_timestamping_constants(crtc, &crtc->mode);

	hrtimer_init(&out->vblank_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	out->vblank_hrtimer.function = &vkms_vblank_simulate;
	out->period_ns = ktime_set(0, vblank->framedur_ns);
	hrtimer_start(&out->vblank_hrtimer, out->period_ns, HRTIMER_MODE_REL);

	return 0;
}