Hi Thomas. On Mon, Mar 30, 2020 at 01:29:16PM +0200, Thomas Zimmermann wrote: > Hi Sam and Lyude, > > thanks for improving the documentation. Below are a few points that I'd > found more understandable. I'm no native speaker, though. > > Am 28.03.20 um 14:20 schrieb Sam Ravnborg: > > Lyude Paul wrote a very good intro to vblank here: > > https://lore.kernel.org/dri-devel/faf63d8a9ed23c16af69762f59d0dca6b2bf085f.camel@xxxxxxxxxx/T/#mce6480be738160e9d07c5d023e88fd78d7a06d27 > > > > Add this to the intro chapter in drm_vblank.c so others > > can benefit from it too. > > > > Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx> > > Co-developed-by: Lyude Paul <lyude@xxxxxxxxxx> > > Cc: Lyude Paul <lyude@xxxxxxxxxx> > > Cc: Daniel Vetter <daniel@xxxxxxxx> > > Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx> > > Cc: Maxime Ripard <mripard@xxxxxxxxxx> > > Cc: Thomas Zimmermann <tzimmermann@xxxxxxx> > > Cc: David Airlie <airlied@xxxxxxxx> > > --- > > drivers/gpu/drm/drm_vblank.c | 15 +++++++++++++++ > > 1 file changed, 15 insertions(+) > > > > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c > > index bcf346b3e486..95cac22d59d1 100644 > > --- a/drivers/gpu/drm/drm_vblank.c > > +++ b/drivers/gpu/drm/drm_vblank.c > > @@ -41,6 +41,21 @@ > > /** > > * DOC: vblank handling > > * > > + * From the perspective of a computer, every time a computer monitor displays > > Possibly change from dative case to genitive: > > "From the computer's perspective," ... > > > + * a new frame it's done by "scanning out" the display image from top to > > + * bottom, one row of pixels at a time. which row of pixels we're on is > > s/which/Which > > The text changes from third person (the computer) to first person > (we're). Makes it harder to read. I'd remove both, "we" and "computer", > and speak of display hardware or scanout engine. > > > + * referred to as the scanline. > > I'd say a scanline is any of them. Maybe say "current scanline"? > > > + * Additionally, there's usually a couple of extra scanlines which we > > "In addition to the display's visible area, there's usually a couple of > extra scanlines that" ... > > > + * scan out, but aren't actually displayed on the screen (these sometimes > > + * get used by HDMI audio and friends, but that's another story). > > + * The period where we're on these scanlines is referred to as the vblank. > > I'd replace vblank with "vertical blanking period." That term is > required in the next paragraph. > > The time when the hardware operates on these invisible scanlines is > referred to as vertical blanking period, or simply vblank. > > > + * > > + * On a lot of display hardware, programming needs to take effect during the > > + * vertical blanking period so that settings like gamma, what frame we're > > "we" again > > > + * scanning out, etc. can be safely changed without showing visual tearing > > + * on the screen. In some unforgiving hardware, some of this programming has > > + * to both start and end in the same vblank - vertical blanking. > > + * > > * Vertical blanking plays a major role in graphics rendering. To achieve > > * tear-free display, users must synchronize page flips and/or rendering to > > * vertical blanking. The DRM API offers ioctls to perform page flips > > > > In any case > > Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Thanks for the detailed feedabck - I have tried to reword it so it better fits the context and have taking into account your suggetions. See other mail for the updated patch. Sam _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
