[PATCH 3/6] drm/bridge: tc358767: Drop line_pixel_subtract

[Marek Vasut]

On 6/4/24 1:12 PM, Alexander Stein wrote:
> Hi Marek,

Hi,

> Am Montag, 3. Juni 2024, 23:25:43 CEST schrieb Marek Vasut:
>> On 6/3/24 2:18 PM, Alexander Stein wrote:
>>> Hi Marek,
>>
>> Hi,
>>
>>> Am Freitag, 31. Mai 2024, 22:39:49 CEST schrieb Marek Vasut:
>>>> This line_pixel_subtract is no longer needed now that the bridge can
>>>> request and obtain specific pixel clock on input to the bridge, with
>>>> clock frequency that matches the Pixel PLL frequency.
>>>>
>>>> The line_pixel_subtract is now always 0, so drop it entirely.
>>>>
>>>> The line_pixel_subtract was not reliable as it never worked when the
>>>> Pixel PLL and input clock were off just so that the required amount
>>>> of pixels to subtract would not be whole integer.
>>>
>>> I think this is based on [1], no?
>>
>> It is.
> 
> Thanks for confirmation.
> 
>>> I was wondering because it was not stated.
>>
>> I thought [1] was already applied, but it seems it was only RBd.
>>
>> I can either apply [1] and then add this on top, so the two commits can
>> be reverted separately if this one breaks something, or squash [1] into
>> this patch and send V2. Which one do you prefer ?
>>
>> The [1] fixes a real nasty issue with DPI output which causes visible
>> image corruption, so I would like to have [1] in, but it is obviously
>> not perfect.
> 
> I can't use DPI anyway, but if [1] actually fixes something for DPI
> I'm okay with having [1] in, which gets mostly reverted in this series.
> But that's up to the maintainers.

It is the FRMSYNC enablement (as suggested by the TC9595 datasheet) 
which fixes the issue. This just makes FRMSYNC work well with other modes.