drm/bridge: tc358767: fix max_tu_symbol value
authorTomi Valkeinen <tomi.valkeinen@ti.com>
Tue, 24 Sep 2019 13:17:02 +0000 (16:17 +0300)
committerAndrzej Hajda <a.hajda@samsung.com>
Thu, 10 Oct 2019 09:15:45 +0000 (11:15 +0200)
commitfd70c7755bf0172ddd33b558aef69c322de3b5cf
treee9ae6d95bc8117c8f4038a1e21b2e9ddb87f8ba2
parentcc635be34eb672a30a4936db30987b7c2e91fb61
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
drivers/gpu/drm/bridge/tc358767.c