max_tu_symbol was programmed to TU_SIZE_RECOMMENDED - 1, which is not what the spec says. The spec says: roundup ((input active video bandwidth in bytes/output active video bandwidth in bytes) * tu_size) It is not quite clear what the above means, but calculating max_tu_symbol = (input Bps / output Bps) * tu_size seems to work and fixes the issues seen. This fixes artifacts in some videomodes (e.g. 1024x768@60 on 2-lanes & 1.62Gbps was pretty bad for me). Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx> --- drivers/gpu/drm/bridge/tc358767.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index 13ade28a36a8..b6aa1bd47e1d 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -677,6 +677,8 @@ static int tc_set_video_mode(struct tc_data *tc, int upper_margin = mode->vtotal - mode->vsync_end; int lower_margin = mode->vsync_start - mode->vdisplay; int vsync_len = mode->vsync_end - mode->vsync_start; + u32 bits_per_pixel = 24; + u32 in_bw, out_bw; /* * Recommended maximum number of symbols transferred in a transfer unit: @@ -684,7 +686,10 @@ static int tc_set_video_mode(struct tc_data *tc, * (output active video bandwidth in bytes)) * Must be less than tu_size. */ - max_tu_symbol = TU_SIZE_RECOMMENDED - 1; + + in_bw = mode->clock * bits_per_pixel / 8; + out_bw = tc->link.base.num_lanes * tc->link.base.rate; + max_tu_symbol = DIV_ROUND_UP(in_bw * TU_SIZE_RECOMMENDED, out_bw); dev_dbg(tc->dev, "set mode %dx%d\n", mode->hdisplay, mode->vdisplay); -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
