On Tue, 18 Jul 2017 14:05:05 -0700 Eric Anholt <eric@xxxxxxxxxx> wrote: > The incoming mode might have a missing vrefresh field if it came from > drmModeSetCrtc(), which the kernel is supposed to calculate using > drm_mode_vrefresh(). We could either use that or the adjusted_mode's > original vrefresh value. > > However, we can maintain a more exact vrefresh value (not just the > integer approximation), by scaling by the ratio of our clocks. > > v2: Use math suggested by Andrzej Hajda instead. > > Signed-off-by: Eric Anholt <eric@xxxxxxxxxx> > --- > drivers/gpu/drm/vc4/vc4_dsi.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c > index 629d372633e6..57213f4e3c72 100644 > --- a/drivers/gpu/drm/vc4/vc4_dsi.c > +++ b/drivers/gpu/drm/vc4/vc4_dsi.c > @@ -866,7 +866,8 @@ static bool vc4_dsi_encoder_mode_fixup(struct drm_encoder *encoder, > adjusted_mode->clock = pixel_clock_hz / 1000 + 1; > > /* Given the new pixel clock, adjust HFP to keep vrefresh the same. */ > - adjusted_mode->htotal = pixel_clock_hz / (mode->vrefresh * mode->vtotal); > + adjusted_mode->htotal = (pixel_clock_hz / 1000 * mode->htotal / > + mode->clock); Hm, I'm not sure I understand this. Shouldn't we have something like: adjusted_mode->htotal = (adjusted_mode->clock * mode->htotal) / mode->clock; Is there a reason for doing '+ 1' when you calculate the adjusted pixel clock rate but not here? > adjusted_mode->hsync_end += adjusted_mode->htotal - mode->htotal; > adjusted_mode->hsync_start += adjusted_mode->htotal - mode->htotal; > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
