[PATCH] drm/bridge: tc358767: fix max_tu_symbol value

Tomi Valkeinen tomi.valkeinen at ti.com
Thu Oct 10 09:25:14 UTC 2019

Hi Andrzej,

On 10/10/2019 12:19, Andrzej Hajda wrote:
> On 24.09.2019 15:17, Tomi Valkeinen wrote:
>> 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 at 60 on 2-lanes &
>> 1.62Gbps was pretty bad for me).
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ti.com>
> Queued to fixes.

If you didn't push this yet, can you drop it for now? This works for all 
the video modes I have tested, but as I mention above, the calculation 
is really not quite clear to me.

I've sent queries to Toshiba about how to calculate this, and I'm hoping 
to get a reply soon.

If you did push it already, that's fine too, as it does improve things.


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