From: Ville Syrjälä Date: Fri, 28 Feb 2020 20:35:49 +0000 (+0200) Subject: drm/i915: Don't check uv_wm in skl_plane_wm_equals() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e7f54e6c198159ff593f1d52707d40a82899cfc7;p=linux.git drm/i915: Don't check uv_wm in skl_plane_wm_equals() The hardware never sees the uv_wm values (apart from uv_wm.min_ddb_alloc affecting the ddb allocation). Thus there is no point in comparing uv_wm to determine if we need to reprogram the watermark registers. So let's check only the rgb/y watermark in skl_plane_wm_equals(). But let's leave a comment behind so that the next person reading this doesn't get as confused as I did when I added this check. If the ddb allocation ends up changing due to uv_wm skl_ddb_add_affected_planes() takes care of adding the plane to the state. TODO: we should perhaps just eliminate uv_wm from the state and simply track the min_ddb_alloc for uv instead. Cc: Matt Roper Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20200228203552.30273-1-ville.syrjala@linux.intel.com Reviewed-by: José Roberto de Souza --- diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index 26572364f893f..43c8081ff0513 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5404,8 +5404,12 @@ static bool skl_plane_wm_equals(struct drm_i915_private *dev_priv, int level, max_level = ilk_wm_max_level(dev_priv); for (level = 0; level <= max_level; level++) { - if (!skl_wm_level_equals(&wm1->wm[level], &wm2->wm[level]) || - !skl_wm_level_equals(&wm1->uv_wm[level], &wm2->uv_wm[level])) + /* + * We don't check uv_wm as the hardware doesn't actually + * use it. It only gets used for calculating the required + * ddb allocation. + */ + if (!skl_wm_level_equals(&wm1->wm[level], &wm2->wm[level])) return false; }