[PATCH 2/2] drm/bridge: lt9611: Do not generate HFP/HBP/HSA and EOT packet

[Marek Vasut]

On 7/5/23 07:46, Jagan Teki wrote:
> On Wed, Jul 5, 2023 at 11:09 AM Dmitry Baryshkov
> <dmitry.baryshkov at linaro.org> wrote:
>>
>> [Adding freedreno@ to cc list]
>>
>> On Wed, 5 Jul 2023 at 08:31, Jagan Teki <jagan at amarulasolutions.com> wrote:
>>>
>>> Hi Amit,
>>>
>>> On Wed, Jul 5, 2023 at 10:15 AM Amit Pundir <amit.pundir at linaro.org> wrote:
>>>>
>>>> Hi Marek,
>>>>
>>>> On Wed, 5 Jul 2023 at 01:48, Marek Vasut <marex at denx.de> wrote:
>>>>>
>>>>> Do not generate the HS front and back porch gaps, the HSA gap and
>>>>> EOT packet, as these packets are not required. This makes the bridge
>>>>> work with Samsung DSIM on i.MX8MM and i.MX8MP.
>>>>
>>>> This patch broke display on Dragonboard 845c (SDM845) devboard running
>>>> AOSP. This is what I see
>>>> https://people.linaro.org/~amit.pundir/db845c-userdebug/v6.5-broken-display/PXL_20230704_150156326.jpg.
>>>> Reverting this patch fixes this regression for me.
>>>
>>> Might be msm dsi host require proper handling on these updated
>>> mode_flags? did they?
>>
>> The msm DSI host supports those flags. Also, I'd like to point out
>> that the patch didn't change the rest of the driver code. So even if
>> drm/msm ignored some of the flags, it should not have caused the
>> issue. Most likely the issue is on the lt9611 side. I's suspect that
>> additional programming is required to make it work with these flags.
> 
> True, But I'm not quite sure, most of these mode_flags were handled
> more on the host. Maybe Marek can comment on this.

So, we have the same flags, but two different controllers produce 
different DSI streams ? Do we have any way to analyze the stream 
produced by each controller, to figure out which one is wrong and which 
one is right ?