DRM: VBLANK: provide valid timestamp for EVENT_FLIP

Message ID 20180926142535.17997-1-Eugeniy.Paltsev@synopsys.com
State New
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Series
  • DRM: VBLANK: provide valid timestamp for EVENT_FLIP
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Commit Message

Eugeniy Paltsev Sept. 26, 2018, 2:25 p.m.
If driver/HW doesn't support vblank functionality (for example
UDL driver, ARCPGU driver, ...) we always have vblank->time == 0.
In result we always provide zero timestamp for
DRM_EVENT_FLIP_COMPLETE. This breaks userspace apps (for example
weston) which relies on timestamp value.

Setup time to provide valid timestamp for DRM_EVENT_FLIP_COMPLETE
event.

Cc: stable@vger.kernel.org
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
---
 drivers/gpu/drm/drm_vblank.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Ville Syrjälä Sept. 26, 2018, 4:37 p.m. | #1
On Wed, Sep 26, 2018 at 05:25:35PM +0300, Eugeniy Paltsev wrote:
> If driver/HW doesn't support vblank functionality (for example
> UDL driver, ARCPGU driver, ...) we always have vblank->time == 0.
> In result we always provide zero timestamp for
> DRM_EVENT_FLIP_COMPLETE. This breaks userspace apps (for example
> weston) which relies on timestamp value.
> 
> Setup time to provide valid timestamp for DRM_EVENT_FLIP_COMPLETE
> event.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
> ---
>  drivers/gpu/drm/drm_vblank.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> index 28cdcf76b6f9..0d19aca48782 100644
> --- a/drivers/gpu/drm/drm_vblank.c
> +++ b/drivers/gpu/drm/drm_vblank.c
> @@ -911,6 +911,15 @@ void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
>  
>  	if (dev->num_crtcs > 0) {

If those drivers don't support vblank stuff why are they calling
drm_vblank_init() w/ num_crtcs > 0? If they didn't they'd take the
else branch which already does what you want.

>  		seq = drm_vblank_count_and_time(dev, pipe, &now);
> +
> +		/*
> +		 * If driver/HW doesn't support vblank functionality we
> +		 * always have vblank->time == 0. Setup time to provide valid
> +		 * timestamp for DRM_EVENT_FLIP_COMPLETE event.
> +		 */
> +		if (!now && e->event.base.type == DRM_EVENT_FLIP_COMPLETE)
> +			now = ktime_get();
> +
>  	} else {
>  		seq = 0;
>  
> -- 
> 2.14.4
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Eugeniy Paltsev Sept. 28, 2018, 2:32 p.m. | #2
On Wed, 2018-09-26 at 19:37 +0300, Ville Syrjälä wrote:
> On Wed, Sep 26, 2018 at 05:25:35PM +0300, Eugeniy Paltsev wrote:
> > If driver/HW doesn't support vblank functionality (for example
> > UDL driver, ARCPGU driver, ...) we always have vblank->time == 0.
> > In result we always provide zero timestamp for
> > DRM_EVENT_FLIP_COMPLETE. This breaks userspace apps (for example
> > weston) which relies on timestamp value.
> > 
> > Setup time to provide valid timestamp for DRM_EVENT_FLIP_COMPLETE
> > event.
> > 
> > Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
> > ---
> >  drivers/gpu/drm/drm_vblank.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
> > index 28cdcf76b6f9..0d19aca48782 100644
> > --- a/drivers/gpu/drm/drm_vblank.c
> > +++ b/drivers/gpu/drm/drm_vblank.c
> > @@ -911,6 +911,15 @@ void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
> >  
> >  	if (dev->num_crtcs > 0) {
> 
> If those drivers don't support vblank stuff why are they calling
> bldrm_vank_init() w/ num_crtcs > 0? If they didn't they'd take the
> else branch which already does what you want.

Hmm...
As I can see UDL call drm_vblank_init() with num_crtcs = 1 but UDL HW
doesn't support vblank at all.
I guess I need to fix it.

> >  		seq = drm_vblank_count_and_time(dev, pipe, &now);
> > +
> > +		/*
> > +		 * If driver/HW doesn't support vblank functionality we
> > +		 * always have vblank->time == 0. Setup time to provide valid
> > +		 * timestamp for DRM_EVENT_FLIP_COMPLETE event.
> > +		 */
> > +		if (!now && e->event.base.type == DRM_EVENT_FLIP_COMPLETE)
> > +			now = ktime_get();
> > +
> >  	} else {
> >  		seq = 0;
> >  
> > -- 
> > 2.14.4
> > 
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://urldefense.proofpoint.com/v2/url?u=https-3A__lists.freedesktop.org_mailman_listinfo_dri-2Ddevel&d=DwIDAw&c=DPL6_X_6JkXFx7AXWqB0tg&r=ZlJN1M
> > riPUTkBKCrPSx67GmaplEUGcAEk9yPtCLdUXI&m=5bbb9SeVXTMPDa1bXQxqlBIOnSdKaKY5W0BkMCgwijE&s=50EhApCZAeMMDUEd6FVpXf5owd1Bi3vn5GaBt0KE2Cw&e=
> 
>

Patch

diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 28cdcf76b6f9..0d19aca48782 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -911,6 +911,15 @@  void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
 
 	if (dev->num_crtcs > 0) {
 		seq = drm_vblank_count_and_time(dev, pipe, &now);
+
+		/*
+		 * If driver/HW doesn't support vblank functionality we
+		 * always have vblank->time == 0. Setup time to provide valid
+		 * timestamp for DRM_EVENT_FLIP_COMPLETE event.
+		 */
+		if (!now && e->event.base.type == DRM_EVENT_FLIP_COMPLETE)
+			now = ktime_get();
+
 	} else {
 		seq = 0;