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

[Tomi Valkeinen]

On 10/10/2019 12:25, Tomi Valkeinen wrote:
> 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.
Just for the record, got a reply from Toshiba, and the patch is correct.

  Tomi

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