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| author | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2019-09-24 16:17:02 +0300 |
|---|---|---|
| committer | Andrzej Hajda <a.hajda@samsung.com> | 2019-10-10 11:15:45 +0200 |
| commit | fd70c7755bf0172ddd33b558aef69c322de3b5cf (patch) | |
| tree | e9ae6d95bc8117c8f4038a1e21b2e9ddb87f8ba2 | |
| parent | cc635be34eb672a30a4936db30987b7c2e91fb61 (diff) | |
| download | linux-stable-fd70c7755bf0172ddd33b558aef69c322de3b5cf.tar.gz linux-stable-fd70c7755bf0172ddd33b558aef69c322de3b5cf.tar.bz2 linux-stable-fd70c7755bf0172ddd33b558aef69c322de3b5cf.zip | |
drm/bridge: tc358767: fix max_tu_symbol value
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@ti.com>
Tested-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190924131702.9988-1-tomi.valkeinen@ti.com
| -rw-r--r-- | drivers/gpu/drm/bridge/tc358767.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c index cebc8e620820..8a8d605021f0 100644 --- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -728,6 +728,8 @@ static int tc_set_video_mode(struct tc_data *tc, int lower_margin = mode->vsync_start - mode->vdisplay; int vsync_len = mode->vsync_end - mode->vsync_start; u32 dp0_syncval; + u32 bits_per_pixel = 24; + u32 in_bw, out_bw; /* * Recommended maximum number of symbols transferred in a transfer unit: @@ -735,7 +737,10 @@ 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); |