diff options
| -rw-r--r-- | drivers/gpu/drm/bridge/samsung-dsim.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c index 8476650c477c..e7e53a9e42af 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->lanes > 1) { + int hfp = adjusted_mode->hsync_start - adjusted_mode->hdisplay; + int remainder = hfp % dsi->lanes; + + if (remainder) { + adjusted_mode->hsync_start += remainder; + adjusted_mode->hsync_end += remainder; + adjusted_mode->htotal += remainder; + } + } + return 0; } |