Messages in this thread | | | Date | Sun, 21 Apr 2024 16:06:24 +0200 | Subject | Re: [PATCH V2 2/2] drm/bridge: samsung-dsim: Fix porch calcalcuation rounding | From | Marek Vasut <> |
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On 2/12/24 12:09 AM, Adam Ford wrote: > When using video sync pulses, the HFP, HBP, and HSA are divided between > the available lanes if there is more than one lane. For certain > timings and lane configurations, the HFP may not be evenly divisible. > If the HFP is rounded down, it ends up being too small which can cause > some monitors to not sync properly. In these instances, adjust htotal > and hsync to round the HFP up, and recalculate the htotal. > > Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de> # Kontron BL i.MX8MM with HDMI monitor > Signed-off-by: Adam Ford <aford173@gmail.com> > --- > V2: No changes > > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c > index 8476650c477c..52939211fe93 100644 > --- a/drivers/gpu/drm/bridge/samsung-dsim.c > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c > @@ -1606,6 +1606,27 @@ static int samsung_dsim_atomic_check(struct drm_bridge *bridge, > adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC); > } > > + /* > + * When using video sync pulses, the HFP, HBP, and HSA are divided between > + * the available lanes if there is more than one lane. For certain > + * timings and lane configurations, the HFP may not be evenly divisible. > + * If the HFP is rounded down, it ends up being too small which can cause > + * some monitors to not sync properly. In these instances, adjust htotal > + * and hsync to round the HFP up, and recalculate the htotal. Through trial > + * and error, it appears that the HBP and HSA do not appearto need the same > + * correction that HFP does. > + */ > + if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE && dsi->lanes > 1) {
Does this also apply to mode with sync events (I suspect it does), so the condition here should likely be if (!...burst mode) , right ?
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